Structure and method of manufacture for acoustic resonator or filter devices using improved fabrication conditions and perimeter structure modifications

ABSTRACT

A method of manufacture for an acoustic resonator or filter device. In an example, the present method can include forming metal electrodes with different geometric areas and profile shapes coupled to a piezoelectric layer overlying a substrate. These metal electrodes can also be formed within cavities of the piezoelectric layer or the substrate with varying geometric areas. Combined with specific dimensional ratios and ion implantations, such techniques can increase device performance metrics. In an example, the present method can include forming various types of perimeter structures surrounding the metal electrodes, which can be on top or bottom of the piezoelectric layer. These perimeter structures can use various combinations of modifications to shape, material, and continuity. These perimeter structures can also be combined with sandbar structures, piezoelectric layer cavities, the geometric variations previously discussed to improve device performance metrics.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority to and is a continuationapplication of U.S. patent application Ser. No. 15/341,218, (AttorneyDocket No. A969R0-000900US) titled “STRUCTURE AND METHOD OF MANUFACTUREFOR ACOUSTIC RESONATOR OR FILTER DEVICES USING IMPROVED FABRICATIONCONDITIONS AND PERIMETER STRUCTURE MODIFICATIONS,” filed Nov. 2, 2016.The present application incorporates by reference, for all purposes, thefollowing concurrently filed patent applications, all commonly owned:U.S. patent application Ser. No. 14/298,057, (Attorney Docket No.A969R0-000100US) titled “RESONANCE CIRCUIT WITH A SINGLE CRYSTALCAPACITOR DIELECTRIC MATERIAL”, filed Jun. 6, 2014 (now U.S. Pat. No.9,673,384 issued Jun. 6, 2017); U.S. patent application Ser. No.14/298,076, (Attorney Docket No. A969R0-000200US) titled “METHOD OFMANUFACTURE FOR SINGLE CRYSTAL CAPACITOR DIELECTRIC FOR A RESONANCECIRCUIT”, filed Jun. 6, 2014 (now U.S. Pat. No. 9,537,465 issued Jan. 3,2017); U.S. patent application Ser. No. 14/298,100, (Attorney Docket No.A969R0-000300US) titled “INTEGRATED CIRCUIT CONFIGURED WITH TWO OR MORESINGLE CRYSTAL ACOUSTIC RESONATOR DEVICES”, filed Jun. 6, 2014 (now U.S.Pat. No. 9,571,061 issued Feb. 14, 2017); U.S. patent application Ser.No. 14/341,314, (Attorney Docket No.: A969R0-000400US) titled “WAFERSCALE PACKAGING”, filed Jul. 25, 2014 (now U.S. Pat. No. 9,805,966issued Oct. 31, 2017); U.S. patent application Ser. No. 14/449,001,(Attorney Docket No.: A969R0-000500US) titled “MOBILE COMMUNICATIONDEVICE CONFIGURED WITH A SINGLE CRYSTAL PIEZO RESONATOR STRUCTURE”,filed Jul. 31, 2014 (now U.S. Pat. No. 9,716,581 issued Jul. 25, 2017);U.S. patent application Ser. No. 14/469,503, (Attorney Docket No.:A969R0-000600US) titled “MEMBRANE SUBSTRATE STRUCTURE FOR SINGLE CRYSTALACOUSTIC RESONATOR DEVICE”, filed Aug. 26, 2014 (now U.S. Pat. No.9,917,568 issued Mar. 13, 2018), and U.S. patent application Ser. No.15/068,510, (Attorney Docket No.: A969R0-000700US) titled “METHOD OFMANUFACTURE FOR SINGLE CRYSTAL ACOUSTIC RESONATOR DEVICES USINGMICRO-VIAS,” filed Mar. 11, 2016.

BACKGROUND OF THE INVENTION

The present invention relates generally to electronic devices. Moreparticularly, the present invention provides techniques related to amethod of manufacture for bulk acoustic wave resonator devices, singlecrystal bulk acoustic wave resonator devices, single crystal filter andresonator devices, and the like. Merely by way of example, the inventionhas been applied to a single crystal resonator device for acommunication device, mobile device, computing device, among others.

Mobile telecommunication devices have been successfully deployedworld-wide. Over a billion mobile devices, including cell phones andsmartphones, were manufactured in a single year and unit volumecontinues to increase year-over-year. With ramp of 4G/LTE in about 2012,and explosion of mobile data traffic, data rich content is driving thegrowth of the smartphone segment—which is expected to reach 2B per annumwithin the next few years. Coexistence of new and legacy standards andthirst for higher data rate requirements is driving RF complexity insmartphones. Unfortunately, limitations exist with conventional RFtechnology that is problematic, and may lead to drawbacks in the future.

From the above, it is seen that techniques for improving electronicdevices are highly desirable.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, techniques generally related toelectronic devices are provided. More particularly, the presentinvention provides techniques related to an acoustic resonator or filterusing wafer level technologies. Merely by way of example, the inventionhas been applied to a resonator device for a communication device,mobile device, computing device, among others.

In an example, the present method provides a method of manufacture foran acoustic resonator or filter device using device layers and cavitieswith varying geometric areas. Specifically, the present method caninclude forming metal electrodes with different geometric areas andprofile shapes coupled to a piezoelectric layer overlying a substrate.These metal electrodes can also be formed within cavities of thepiezoelectric layer or the substrate with varying geometric areas.Combined with specific dimensional ratios and ion implantations, suchtechniques can increase device performance metrics.

In an example, the present method provides a method of manufacture foran acoustic resonator or filter device using perimeter structuresconfigured near electrodes. In an example, the present method caninclude forming various types of perimeter structures surrounding one ormore metal electrodes, which can be formed on top or bottom of thepiezoelectric layer. These perimeter structures can use variouscombinations of modifications to shape, material, and continuity. Theseperimeter structures can also be combined with sandbar structures,piezoelectric layer cavities, the geometric variations previouslydiscussed to improve device performance metrics.

A further understanding of the nature and advantages of the inventionmay be realized by reference to the latter portions of the specificationand attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the present invention, reference ismade to the accompanying drawings. Understanding that these drawings arenot to be considered limitations in the scope of the invention, thepresently described embodiments and the presently understood best modeof the invention are described with additional detail through use of theaccompanying drawings in which:

FIG. 1A is a simplified diagram illustrating an acoustic resonatordevice having topside interconnections according to an example of thepresent invention.

FIG. 1B is a simplified diagram illustrating an acoustic resonatordevice having bottom-side interconnections according to an example ofthe present invention.

FIG. 1C is a simplified diagram illustrating an acoustic resonatordevice having interposer/cap-free structure interconnections accordingto an example of the present invention.

FIG. 1D is a simplified diagram illustrating an acoustic resonatordevice having interposer/cap-free structure interconnections with ashared backside trench according to an example of the present invention.

FIGS. 2 and 3 are simplified diagrams illustrating steps for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention.

FIG. 4A is a simplified diagram illustrating a step for a methodcreating a topside micro-trench according to an example of the presentinvention.

FIGS. 4B and 4C are simplified diagrams illustrating alternative methodsfor conducting the method step of forming a topside micro-trench asdescribed in FIG. 4A.

FIGS. 4D and 4E are simplified diagrams illustrating an alternativemethod for conducting the method step of forming a topside micro-trenchas described in FIG. 4A.

FIGS. 5 to 8 are simplified diagrams illustrating steps for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention.

FIG. 9A is a simplified diagram illustrating a method step for formingbackside trenches according to an example of the present invention.

FIGS. 9B and 9C are simplified diagrams illustrating an alternativemethod for conducting the method step of forming backside trenches, asdescribed in FIG. 9A, and simultaneously singulating a seed substrateaccording to an example of the present invention.

FIG. 10 is a simplified diagram illustrating a method step formingbackside metallization and electrical interconnections between top andbottom sides of a resonator according to an example of the presentinvention.

FIGS. 11A and 11B are simplified diagrams illustrating alternative stepsfor a method of manufacture for an acoustic resonator device accordingto an example of the present invention.

FIGS. 12A to 12E are simplified diagrams illustrating steps for a methodof manufacture for an acoustic resonator device using a blind viainterposer according to an example of the present invention.

FIG. 13 is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention.

FIGS. 14A to 14G are simplified diagrams illustrating method steps for acap wafer process for an acoustic resonator device according to anexample of the present invention.

FIGS. 15A-15E are simplified diagrams illustrating method steps formaking an acoustic resonator device with shared backside trench, whichcan be implemented in both interposer/cap and interposer free versions,according to examples of the present invention.

FIG. 16 is a simplified flow diagram illustrating a method formanufacturing a single-crystal piezoelectric layer according to anexample of the present invention.

FIG. 17 is a simplified graph illustrating the results of forming apiezoelectric layer for an acoustic resonator device according to anexample of the present invention. The graph highlights the ability of totailor the acoustic properties of the material for a given Aluminum molefraction. Such flexibility allows for the resulting resonator propertiesto be tailored to the individual application.

FIG. 18A is a simplified diagram illustrating a method for forming apiezoelectric layer for an acoustic resonator device according to anexample of the present invention.

FIG. 18B is a simplified diagram illustrating a method for forming apiezoelectric layer for an acoustic resonator device according to anexample of the present invention.

FIG. 18C is a simplified diagram illustrating a method for forming apiezoelectric layer for an acoustic resonator device according to anexample of the present invention.

FIG. 19A is a simplified diagram illustrating a top view of an acousticresonator device according to an example of the present invention.

FIG. 19B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 19A.

FIG. 20A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with electrode boundary modificationsaccording to an example of the present invention.

FIGS. 20B through 20G are simplified diagrams illustratingcross-sectional views of portions of acoustic resonator devices withelectrode boundary modifications according to an example of the presentinvention.

FIG. 21A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with grooved electrode boundarymodifications according to an example of the present invention.

FIGS. 21B through 21G are simplified diagrams illustratingcross-sectional views of portions of acoustic resonator devices withgrooved electrode boundary modifications according to an example of thepresent invention.

FIG. 22A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with a grooved piezoelectric layeraccording to an example of the present invention.

FIGS. 22B and 22C are simplified diagrams illustrating cross-sectionalviews of portions of acoustic resonator devices with groovedpiezoelectric layers according to an example of the present invention.

FIG. 23A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with a grooved piezoelectric sub-surfacelayer according to an example of the present invention.

FIGS. 23B and 23C are simplified diagrams illustrating cross-sectionalviews of portions of acoustic resonator devices with groovedpiezoelectric sub-surface layers according to an example of the presentinvention.

FIG. 24A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with electrode perimeter structuremodification according to an example of the present invention.

FIGS. 24B through 24E are simplified diagrams illustratingcross-sectional views of portions of acoustic resonator devices withelectrode perimeter structure modification according to an example ofthe present invention.

FIGS. 25A through 25D are simplified diagrams illustratingcross-sectional views of a an acoustic resonator device subjected to anion implantation process according to an example of the presentinvention.

FIG. 26A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with spatial modifications according to anexample of the present invention.

FIGS. 26B through 26E are simplified diagrams illustratingcross-sectional views of portions of acoustic resonator devices withspatial modifications according to an example of the present invention.

FIG. 27A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device according to an example of the presentinvention.

FIG. 27B is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with frequency offset structure accordingto an example of the present invention.

FIG. 28A is a simplified diagram illustrating a top view of a multipleacoustic resonator device according to an example of the presentinvention.

FIG. 28B is a simplified diagram illustrating a cross-sectional view ofthe multiple acoustic resonator device shown in FIG. 28A.

FIG. 29A is a simplified diagram illustrating a top view of a multipleacoustic resonator device according to an example of the presentinvention.

FIG. 29B is a simplified diagram illustrating a cross-sectional view ofthe multiple acoustic resonator device shown in FIG. 29A.

FIG. 30A is a simplified diagram illustrating a top view of an acousticresonator device according to an example of the present invention, whichis further described in FIGS. 31A through 39D.

FIG. 30B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 30A, which is furtherdescribed in FIGS. 31A through 39D.

FIG. 31A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside metal perimeterstructure modifications according to an example of the presentinvention.

FIG. 31B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 31A.

FIG. 31C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside metal perimeterstructure modifications according to an example of the presentinvention.

FIG. 31D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 31C.

FIG. 32A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside metal perimeterstructure modifications according to an example of the presentinvention.

FIG. 32B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 32A.

FIG. 32C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside metal perimeterstructure modifications according to an example of the presentinvention.

FIG. 32D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 32C.

FIG. 33A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric perimeterstructure modifications according to an example of the presentinvention.

FIG. 33B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 33A.

FIG. 33C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric perimeterstructure modifications according to an example of the presentinvention.

FIG. 33D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 33C.

FIG. 34A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric perimeterstructure modifications according to an example of the presentinvention.

FIG. 34B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 34A.

FIG. 34C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric perimeterstructure modifications according to an example of the presentinvention.

FIG. 34D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 34C.

FIG. 35A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 35B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 35A.

FIG. 35C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 35D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 35C.

FIG. 36A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 36B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 36A.

FIG. 36C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 36D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 36C.

FIG. 37A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 37B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 37A.

FIG. 37C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 37D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 37C.

FIG. 38A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 38B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 38A.

FIG. 38C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 38D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 38C.

FIG. 39A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 39B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 39A.

FIG. 39C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention.

FIG. 39D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 39C.

FIG. 40A is a simplified diagram illustrating a top view of an acousticresonator device with subsurface modifications according to an exampleof the present invention.

FIG. 40B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 40A.

FIG. 41A is a simplified diagram illustrating a top view of an acousticresonator device with perimeter structure modifications according to anexample of the present invention.

FIG. 41B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 41A.

FIG. 42 is a simplified diagram illustrating a top view of an acousticresonator device with perimeter structure modifications according to anexample of the present invention.

FIG. 43 is a simplified diagram illustrating a top view of an acousticresonator device with perimeter structure modifications according to anexample of the present invention.

FIG. 44A is a simplified diagram illustrating a top view of an acousticresonator device with perimeter structure modifications according to anexample of the present invention.

FIG. 44B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 44A.

FIG. 44C is a simplified diagram illustrating a cross-sectional view ofa portion of the acoustic resonator device shown in FIGS. 44A and 44B.

FIG. 44D is a simplified diagram illustrating a cross-sectional view ofa portion of the acoustic resonator device shown in FIGS. 44A and 44B.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, techniques generally related toelectronic devices are provided. More particularly, the presentinvention provides techniques related to a single crystal acousticresonator using wafer level technologies. Merely by way of example, theinvention has been applied to a resonator device for a communicationdevice, mobile device, computing device, among others.

FIG. 1A is a simplified diagram illustrating an acoustic resonatordevice 101 having topside interconnections according to an example ofthe present invention. As shown, device 101 includes a thinned seedsubstrate 112 with an overlying single crystal piezoelectric layer 120,which has a micro-via 129. The micro-via 129 can include a topsidemicro-trench 121, a topside metal plug 146, a backside trench 114, and abackside metal plug 147. Although device 101 is depicted with a singlemicro-via 129, device 101 may have multiple micro-vias. A topside metalelectrode 130 is formed overlying the piezoelectric layer 120. A top capstructure is bonded to the piezoelectric layer 120. This top capstructure includes an interposer substrate 119 with one or morethrough-vias 151 that are connected to one or more top bond pads 143,one or more bond pads 144, and topside metal 145 with topside metal plug146. Solder balls 170 are electrically coupled to the one or more topbond pads 143.

The thinned substrate 112 has the first and second backside trenches113, 114. A backside metal electrode 131 is formed underlying a portionof the thinned seed substrate 112, the first backside trench 113, andthe topside metal electrode 130. The backside metal plug 147 is formedunderlying a portion of the thinned seed substrate 112, the secondbackside trench 114, and the topside metal 145. This backside metal plug147 is electrically coupled to the topside metal plug 146 and thebackside metal electrode 131. A backside cap structure 161 is bonded tothe thinned seed substrate 112, underlying the first and second backsidetrenches 113, 114. Further details relating to the method of manufactureof this device will be discussed starting from FIG. 2.

FIG. 1B is a simplified diagram illustrating an acoustic resonatordevice 102 having backside interconnections according to an example ofthe present invention. As shown, device 101 includes a thinned seedsubstrate 112 with an overlying piezoelectric layer 120, which has amicro-via 129. The micro-via 129 can include a topside micro-trench 121,a topside metal plug 146, a backside trench 114, and a backside metalplug 147. Although device 102 is depicted with a single micro-via 129,device 102 may have multiple micro-vias. A topside metal electrode 130is formed overlying the piezoelectric layer 120. A top cap structure isbonded to the piezoelectric layer 120. This top cap structure 119includes bond pads which are connected to one or more bond pads 144 andtopside metal 145 on piezoelectric layer 120. The topside metal 145includes a topside metal plug 146.

The thinned substrate 112 has the first and second backside trenches113, 114. A backside metal electrode 131 is formed underlying a portionof the thinned seed substrate 112, the first backside trench 113, andthe topside metal electrode 130. A backside metal plug 147 is formedunderlying a portion of the thinned seed substrate 112, the secondbackside trench 114, and the topside metal plug 146. This backside metalplug 147 is electrically coupled to the topside metal plug 146. Abackside cap structure 162 is bonded to the thinned seed substrate 112,underlying the first and second backside trenches. One or more backsidebond pads (171, 172, 173) are formed within one or more portions of thebackside cap structure 162. Solder balls 170 are electrically coupled tothe one or more backside bond pads 171-173. Further details relating tothe method of manufacture of this device will be discussed starting fromFIG. 14A.

FIG. 1C is a simplified diagram illustrating an acoustic resonatordevice having interposer/cap-free structure interconnections accordingto an example of the present invention. As shown, device 103 includes athinned seed substrate 112 with an overlying single crystalpiezoelectric layer 120, which has a micro-via 129. The micro-via 129can include a topside micro-trench 121, a topside metal plug 146, abackside trench 114, and a backside metal plug 147. Although device 103is depicted with a single micro-via 129, device 103 may have multiplemicro-vias. A topside metal electrode 130 is formed overlying thepiezoelectric layer 120. The thinned substrate 112 has the first andsecond backside trenches 113, 114. A backside metal electrode 131 isformed underlying a portion of the thinned seed substrate 112, the firstbackside trench 113, and the topside metal electrode 130. A backsidemetal plug 147 is formed underlying a portion of the thinned seedsubstrate 112, the second backside trench 114, and the topside metal145. This backside metal plug 147 is electrically coupled to the topsidemetal plug 146 and the backside metal electrode 131. Further detailsrelating to the method of manufacture of this device will be discussedstarting from FIG. 2.

FIG. 1D is a simplified diagram illustrating an acoustic resonatordevice having interposer/cap-free structure interconnections with ashared backside trench according to an example of the present invention.As shown, device 104 includes a thinned seed substrate 112 with anoverlying single crystal piezoelectric layer 120, which has a micro-via129. The micro-via 129 can include a topside micro-trench 121, a topsidemetal plug 146, and a backside metal 147. Although device 104 isdepicted with a single micro-via 129, device 104 may have multiplemicro-vias. A topside metal electrode 130 is formed overlying thepiezoelectric layer 120. The thinned substrate 112 has a first backsidetrench 113. A backside metal electrode 131 is formed underlying aportion of the thinned seed substrate 112, the first backside trench113, and the topside metal electrode 130. A backside metal 147 is formedunderlying a portion of the thinned seed substrate 112, the secondbackside trench 114, and the topside metal 145. This backside metal 147is electrically coupled to the topside metal plug 146 and the backsidemetal electrode 131. Further details relating to the method ofmanufacture of this device will be discussed starting from FIG. 2.

FIGS. 2 and 3 are simplified diagrams illustrating steps for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention. This method illustrates the process forfabricating an acoustic resonator device similar to that shown in FIG.1A. FIG. 2 can represent a method step of providing a partiallyprocessed piezoelectric substrate. As shown, device 102 includes a seedsubstrate 110 with a piezoelectric layer 120 formed overlying. In aspecific example, the seed substrate can include silicon, siliconcarbide, aluminum oxide, or single crystal aluminum gallium nitridematerials, or the like. The piezoelectric layer 120 can include apiezoelectric single crystal layer or a thin film piezoelectric singlecrystal layer.

FIG. 3 can represent a method step of forming a top side metallizationor top resonator metal electrode 130. In a specific example, the topsidemetal electrode 130 can include a molybdenum, aluminum, ruthenium, ortitanium material, or the like and combinations thereof. This layer canbe deposited and patterned on top of the piezoelectric layer by alift-off process, a wet etching process, a dry etching process, a metalprinting process, a metal laminating process, or the like. The lift-offprocess can include a sequential process of lithographic patterning,metal deposition, and lift-off steps to produce the topside metal layer.The wet/dry etching processes can includes sequential processes of metaldeposition, lithographic patterning, metal deposition, and metal etchingsteps to produce the topside metal layer. Those of ordinary skill in theart will recognize other variations, modifications, and alternatives.

FIG. 4A is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device 401 according to an exampleof the present invention. This figure can represent a method step offorming one or more topside micro-trenches 121 within a portion of thepiezoelectric layer 120. This topside micro-trench 121 can serve as themain interconnect junction between the top and bottom sides of theacoustic membrane, which will be developed in later method steps. In anexample, the topside micro-trench 121 is extends all the way through thepiezoelectric layer 120 and stops in the seed substrate 110. Thistopside micro-trench 121 can be formed through a dry etching process, alaser drilling process, or the like. FIGS. 4B and 4C describe theseoptions in more detail.

FIGS. 4B and 4C are simplified diagrams illustrating alternative methodsfor conducting the method step as described in FIG. 4A. As shown, FIG.4B represents a method step of using a laser drill, which can quicklyand accurately form the topside micro-trench 121 in the piezoelectriclayer 120. In an example, the laser drill can be used to form nominal 50um holes, or holes between 10 um and 500 um in diameter, through thepiezoelectric layer 120 and stop in the seed substrate 110 below theinterface between layers 120 and 110. A protective layer 122 can beformed overlying the piezoelectric layer 120 and the topside metalelectrode 130. This protective layer 122 can serve to protect the devicefrom laser debris and to provide a mask for the etching of the topsidemicro-via 121. In a specific example, the laser drill can be an 11 Whigh power diode-pumped UV laser, or the like. This mask 122 can besubsequently removed before proceeding to other steps. The mask may alsobe omitted from the laser drilling process, and air flow can be used toremove laser debris.

FIG. 4C can represent a method step of using a dry etching process toform the topside micro-trench 121 in the piezoelectric layer 120. Asshown, a lithographic masking layer 123 can be forming overlying thepiezoelectric layer 120 and the topside metal electrode 130. The topsidemicro-trench 121 can be formed by exposure to plasma, or the like.

FIGS. 4D and 4E are simplified diagrams illustrating an alternativemethod for conducting the method step as described in FIG. 4A. Thesefigures can represent the method step of manufacturing multiple acousticresonator devices simultaneously. In FIG. 4D, two devices are shown onDie #1 and Die #2, respectively. FIG. 4E shows the process of forming amicro-via 121 on each of these dies while also etching a scribe line 124or dicing line. In an example, the etching of the scribe line 124singulates and relieves stress in the piezoelectric single crystal layer120.

FIGS. 5 to 8 are simplified diagrams illustrating steps for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention. FIG. 5 can represent the method step of formingone or more bond pads 140 and forming a topside metal 141 electricallycoupled to at least one of the bond pads 140. The topside metal 141 caninclude a topside metal plug 146 formed within the topside micro-trench121. In a specific example, the topside metal plug 146 fills the topsidemicro-trench 121 to form a topside portion of a micro-via.

In an example, the bond pads 140 and the topside metal 141 can include agold material or other interconnect metal material depending upon theapplication of the device. These metal materials can be formed by alift-off process, a wet etching process, a dry etching process, ascreen-printing process, an electroplating process, a metal printingprocess, or the like. In a specific example, the deposited metalmaterials can also serve as bond pads for a cap structure, which will bedescribed below.

FIG. 6 can represent a method step for preparing the acoustic resonatordevice for bonding, which can be a hermetic bonding. As shown, a top capstructure is positioned above the partially processed acoustic resonatordevice as described in the previous figures. The top cap structure canbe formed using an interposer substrate 119 in two configurations: fullyprocessed interposer version 601 (through glass via) and partiallyprocessed interposer version 602 (blind via version). In the 601version, the interposer substrate 119 includes through-via structures151 that extend through the interposer substrate 119 and areelectrically coupled to bottom bond pads 142 and top bond pads 143. Inthe 602 version, the interposer substrate 119 includes blind viastructures 152 that only extend through a portion of the interposersubstrate 119 from the bottom side. These blind via structures 152 arealso electrically coupled to bottom bond pads 142. In a specificexample, the interposer substrate can include a silicon, glass,smart-glass, or other like material.

FIG. 7 can represent a method step of bonding the top cap structure tothe partially processed acoustic resonator device. As shown, theinterposer substrate 119 is bonded to the piezoelectric layer by thebond pads (140, 142) and the topside metal 141, which are now denoted asbond pad 144 and topside metal 145. This bonding process can be doneusing a compression bond method or the like. FIG. 8 can represent amethod step of thinning the seed substrate 110, which is now denoted asthinned seed substrate 111. This substrate thinning process can includegrinding and etching processes or the like. In a specific example, thisprocess can include a wafer backgrinding process followed by stressremoval, which can involve dry etching, CMP polishing, or annealingprocesses.

FIG. 9A is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device 901 according to an exampleof the present invention. FIG. 9A can represent a method step forforming backside trenches 113 and 114 to allow access to thepiezoelectric layer from the backside of the thinned seed substrate 111.In an example, the first backside trench 113 can be formed within thethinned seed substrate 111 and underlying the topside metal electrode130. The second backside trench 114 can be formed within the thinnedseed substrate 111 and underlying the topside micro-trench 121 andtopside metal plug 146. This substrate is now denoted thinned substrate112. In a specific example, these trenches 113 and 114 can be formedusing deep reactive ion etching (DRIE) processes, Bosch processes, orthe like. The size, shape, and number of the trenches may vary with thedesign of the acoustic resonator device. In various examples, the firstbackside trench may be formed with a trench shape similar to a shape ofthe topside metal electrode or a shape of the backside metal electrode.The first backside trench may also be formed with a trench shape that isdifferent from both a shape of the topside metal electrode and thebackside metal electrode.

FIGS. 9B and 9C are simplified diagrams illustrating an alternativemethod for conducting the method step as described in FIG. 9A. LikeFIGS. 4D and 4E, these figures can represent the method step ofmanufacturing multiple acoustic resonator devices simultaneously. InFIG. 9B, two devices with cap structures are shown on Die #1 and Die #2,respectively. FIG. 9C shows the process of forming backside trenches(113, 114) on each of these dies while also etching a scribe line 115 ordicing line. In an example, the etching of the scribe line 115 providesan optional way to singulate the backside wafer 112.

FIG. 10 is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device 1000 according to anexample of the present invention. This figure can represent a methodstep of forming a backside metal electrode 131 and a backside metal plug147 within the backside trenches of the thinned seed substrate 112. Inan example, the backside metal electrode 131 can be formed underlyingone or more portions of the thinned substrate 112, within the firstbackside trench 113, and underlying the topside metal electrode 130.This process completes the resonator structure within the acousticresonator device. The backside metal plug 147 can be formed underlyingone or more portions of the thinned substrate 112, within the secondbackside trench 114, and underlying the topside micro-trench 121. Thebackside metal plug 147 can be electrically coupled to the topside metalplug 146 and the backside metal electrode 131. In a specific example,the backside metal electrode 130 can include a molybdenum, aluminum,ruthenium, or titanium material, or the like and combinations thereof.The backside metal plug can include a gold material, low resistivityinterconnect metals, electrode metals, or the like. These layers can bedeposited using the deposition methods described previously.

FIGS. 11A and 11B are simplified diagrams illustrating alternative stepsfor a method of manufacture for an acoustic resonator device accordingto an example of the present invention. These figures show methods ofbonding a backside cap structure underlying the thinned seed substrate112. In FIG. 11A, the backside cap structure is a dry film cap 161,which can include a permanent photo-imageable dry film such as a soldermask, polyimide, or the like. Bonding this cap structure can becost-effective and reliable, but may not produce a hermetic seal. InFIG. 11B, the backside cap structure is a substrate 162, which caninclude a silicon, glass, or other like material. Bonding this substratecan provide a hermetic seal, but may cost more and require additionalprocesses. Depending upon application, either of these backside capstructures can be bonded underlying the first and second backside vias.

FIGS. 12A to 12E are simplified diagrams illustrating steps for a methodof manufacture for an acoustic resonator device according to an exampleof the present invention. More specifically, these figures describeadditional steps for processing the blind via interposer “602” versionof the top cap structure. FIG. 12A shows an acoustic resonator device1201 with blind vias 152 in the top cap structure. In FIG. 12B, theinterposer substrate 119 is thinned, which forms a thinned interposersubstrate 118, to expose the blind vias 152. This thinning process canbe a combination of a grinding process and etching process as describedfor the thinning of the seed substrate. In FIG. 12C, a redistributionlayer (RDL) process and metallization process can be applied to createtop cap bond pads 160 that are formed overlying the blind vias 152 andare electrically coupled to the blind vias 152. As shown in FIG. 12D, aball grid array (BGA) process can be applied to form solder balls 170overlying and electrically coupled to the top cap bond pads 160. Thisprocess leaves the acoustic resonator device ready for wire bonding 171,as shown in FIG. 12E.

FIG. 13 is a simplified diagram illustrating a step for a method ofmanufacture for an acoustic resonator device according to an example ofthe present invention. As shown, device 1300 includes two fullyprocessed acoustic resonator devices that are ready to singulation tocreate separate devices. In an example, the die singulation process canbe done using a wafer dicing saw process, a laser cut singulationprocess, or other processes and combinations thereof.

FIGS. 14A to 14G are simplified diagrams illustrating steps for a methodof manufacture for an acoustic resonator device according to an exampleof the present invention. This method illustrates the process forfabricating an acoustic resonator device similar to that shown in FIG.1B. The method for this example of an acoustic resonator can go throughsimilar steps as described in FIGS. 1-5. FIG. 14A shows where thismethod differs from that described previously. Here, the top capstructure substrate 119 and only includes one layer of metallizationwith one or more bottom bond pads 142. Compared to FIG. 6, there are novia structures in the top cap structure because the interconnectionswill be formed on the bottom side of the acoustic resonator device.

FIGS. 14B to 14F depict method steps similar to those described in thefirst process flow. FIG. 14B can represent a method step of bonding thetop cap structure to the piezoelectric layer 120 through the bond pads(140, 142) and the topside metal 141, now denoted as bond pads 144 andtopside metal 145 with topside metal plug 146. FIG. 14C can represent amethod step of thinning the seed substrate 110, which forms a thinnedseed substrate 111, similar to that described in FIG. 8. FIG. 14D canrepresent a method step of forming first and second backside trenches,similar to that described in FIG. 9A. FIG. 14E can represent a methodstep of forming a backside metal electrode 131 and a backside metal plug147, similar to that described in FIG. 10. FIG. 14F can represent amethod step of bonding a backside cap structure 162, similar to thatdescribed in FIGS. 11A and 11B.

FIG. 14G shows another step that differs from the previously describedprocess flow. Here, the backside bond pads 171, 172, and 173 are formedwithin the backside cap structure 162. In an example, these backsidebond pads 171-173 can be formed through a masking, etching, and metaldeposition processes similar to those used to form the other metalmaterials. A BGA process can be applied to form solder balls 170 incontact with these backside bond pads 171-173, which prepares theacoustic resonator device 1407 for wire bonding.

FIGS. 15A to 15E are simplified diagrams illustrating steps for a methodof manufacture for an acoustic resonator device according to an exampleof the present invention. This method illustrates the process forfabricating an acoustic resonator device similar to that shown in FIG.1B. The method for this example can go through similar steps asdescribed in FIG. 1-5. FIG. 15A shows where this method differs fromthat described previously. A temporary carrier 218 with a layer oftemporary adhesive 217 is attached to the substrate. In a specificexample, the temporary carrier 218 can include a glass wafer, a siliconwafer, or other wafer and the like.

FIGS. 15B to 15F depict method steps similar to those described in thefirst process flow. FIG. 15B can represent a method step of thinning theseed substrate 110, which forms a thinned substrate 111, similar to thatdescribed in FIG. 8. In a specific example, the thinning of the seedsubstrate 110 can include a back side grinding process followed by astress removal process. The stress removal process can include a dryetch, a Chemical Mechanical Planarization (CMP), and annealingprocesses.

FIG. 15C can represent a method step of forming a shared backside trench113, similar to the techniques described in FIG. 9A. The main differenceis that the shared backside trench is configured underlying both topsidemetal electrode 130, topside micro-trench 121, and topside metal plug146. In an example, the shared backside trench 113 is a backsideresonator cavity that can vary in size, shape (all possible geometricshapes), and side wall profile (tapered convex, tapered concave, orright angle). In a specific example, the forming of the shared backsidetrench 113 can include a litho-etch process, which can include aback-to-front alignment and dry etch of the backside substrate 111. Thepiezoelectric layer 120 can serve as an etch stop layer for the formingof the shared backside trench 113.

FIG. 15D can represent a method step of forming a backside metalelectrode 131 and a backside metal 147, similar to that described inFIG. 10. In an example, the forming of the backside metal electrode 131can include a deposition and patterning of metal materials within theshared backside trench 113. Here, the backside metal 131 serves as anelectrode and the backside plug/connect metal 147 within the micro-via121. The thickness, shape, and type of metal can vary as a function ofthe resonator/filter design. As an example, the backside electrode 131and via plug metal 147 can be different metals. In a specific example,these backside metals 131, 147 can either be deposited and patterned onthe surface of the piezoelectric layer 120 or rerouted to the backsideof the substrate 112. In an example, the backside metal electrode may bepatterned such that it is configured within the boundaries of the sharedbackside trench such that the backside metal electrode does not come incontact with one or more side-walls of the seed substrate created duringthe forming of the shared backside trench.

FIG. 15E can represent a method step of bonding a backside cap structure162, similar to that described in FIGS. 11A and 11B, following ade-bonding of the temporary carrier 218 and cleaning of the topside ofthe device to remove the temporary adhesive 217. Those of ordinary skillin the art will recognize other variations, modifications, andalternatives of the methods steps described previously.

According to an example, the present invention includes a method forforming a piezoelectric layer to fabricate an acoustic resonator device.More specifically, the present method includes forming a single crystalmaterial to be used to fabricate the acoustic resonator device. Bymodifying the strain state of the III-Nitride (III-N) crystal lattice,the present method can change the piezoelectric properties of the singlecrystal material to adjust the acoustic properties of subsequent devicesfabricated from this material. In a specific example, the method forforming the strained single crystal material can include modification ofgrowth conditions of individual layers by employing one or a combinationof the following parameters; gas phase reactant ratios, growth pressure,growth temperature, and introduction of impurities.

In an example, the single crystal material is grown epitaxially upon asubstrate. Methods for growing the single crystal material can includemetal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy(MBE), hydride vapor phase epitaxy (HVPE), atomic layer deposition(ALD), or the like. Various process conditions can be selectively variedto change the piezoelectric properties of the single crystal material.These process conditions can include temperature, pressure, layerthickness, gas phase ratios, and the like. For example, the temperatureconditions for films containing aluminum (Al) and gallium (Ga) and theiralloys can range from about 800 to about 1500 degrees Celsius. Thetemperature conditions for films containing Al, Ga, and indium (In) andtheir alloys can range from about 600 to about 1000 degrees Celsius. Inanother example, the pressure conditions for films containing Al, Ga,and In and their alloys can range from about 1 E-4 Ton to about 900Torr.

FIG. 16 is a flow diagram illustrating a method for manufacturing asingle-crystal piezoelectric layer according to an example of thepresent invention. The following steps are merely examples and shouldnot unduly limit the scope of the claims herein. One of ordinary skillin the art would recognize many other variations, modifications, andalternatives. For example, various steps outlined below may be added,removed, modified, rearranged, repeated, and/or overlapped, ascontemplated within the scope of the invention. A typical growth process1600 can be outlined as follows:

-   -   1601. Provide a substrate having the required material        properties and crystallographic orientation. Various substrates        can be used in the present method for fabricating an acoustic        resonator device such as Silicon, Sapphire, Silicon Carbide,        Gallium Nitride (GaN) or Aluminum Nitride (AlN) bulk substrates.        The present method can also use GaN templates, AlN templates,        and Al_(x)Ga_(1-x)N templates (where x varies between 0.0 and        1.0). These substrates and templates can have polar, non-polar,        or semi-polar crystallographic orientations. Those of ordinary        skill in the art will recognize other variations, modifications,        and alternatives;    -   1602. Place the selected substrate into a processing chamber        within a controlled environment;    -   1603. Heat the substrate to a first desired temperature. At a        reduced pressure between 5-800 mbar the substrates are heated to        a temperature in the range of 1100°-1350° C. in the presence of        purified hydrogen gas as a means to clean the exposed surface of        the substrate. The purified hydrogen flow shall be in the range        of 5-30 slpm (standard liter per minute) and the purity of the        gas should exceed 99.9995%;    -   1604. Cool the substrate to a second desired temperature. After        10-15 minutes at elevated temperature, the substrate surface        temperature should be reduced by 100-200° C.; the temperature        offset here is determined by the selection of substrate material        and the initial layer to be grown (Highlighted in FIGS. 18A-C);    -   1605. Introduce reactants to the processing chamber. After the        temperature has stabilized the Group III and Group V reactants        are introduced to the processing chamber and growth is        initiated.    -   1606. Upon completion of the nucleation layer the growth chamber        pressures, temperatures, and gas phase mixtures may be further        adjusted to grow the layer or plurality of layers of interest        for the acoustic resonator device.    -   1607. During the film growth process the strain-state of the        material may be modulated via the modification of growth        conditions or by the controlled introduction of impurities into        the film (as opposed to the modification of the electrical        properties of the film).    -   1608. At the conclusion of the growth process the Group III        reactants are turned off and the temperature resulting film or        films are controllably lowered to room. The rate of thermal        change is dependent upon the layer or plurality of layers grown        and in the preferred embodiment is balanced such that the        physical parameters of the substrate including films are        suitable for subsequent processing.

Referring to step 1605, the growth of the single crystal material can beinitiated on a substrate through one of several growth methods: directgrowth upon a nucleation layer, growth upon a super lattice nucleationlayer, and growth upon a graded transition nucleation layer. The growthof the single crystal material can be homoepitaxial, heteroepitaxial, orthe like. In the homoepitaxial method, there is a minimal latticemismatch between the substrate and the films such as the case for anative III-N single crystal substrate material. In the heteroepitaxialmethod, there is a variable lattice mismatch between substrate and filmbased on in-plane lattice parameters. As further described below, thecombinations of layers in the nucleation layer can be used to engineerstrain in the subsequently formed structure.

Referring to step 1606, various substrates can be used in the presentmethod for fabricating an acoustic resonator device. Silicon substratesof various crystallographic orientations may be used. Additionally, thepresent method can use sapphire substrates, silicon carbide substrates,gallium nitride (GaN) bulk substrates, or aluminum nitride (AlN) bulksubstrates. The present method can also use GaN templates, AlNtemplates, and Al_(x)Ga_(1-x)N templates (where x varies between 0.0 and1.0). These substrates and templates can have polar, non-polar, orsemi-polar crystallographic orientations. Those of ordinary skill in theart will recognize other variations, modifications, and alternatives.

In an example, the present method involves controlling materialcharacteristics of the nucleation and piezoelectric layer(s). In aspecific example, these layers can include single crystal materials thatare configured with defect densities of less than 1 E+11 defects persquare centimeter. The single crystal materials can include alloysselected from at least one of the following: AlN, AlGaN, GaN, InN,InGaN, AlInN, AlInGaN, and BN. In various examples, any single orcombination of the aforementioned materials can be used for thenucleation layer(s) and/or the piezoelectric layer(s) of the devicestructure.

According to an example, the present method involves strain engineeringvia growth parameter modification. More specifically, the methodinvolves changing the piezoelectric properties of the epitaxial films inthe piezoelectric layer via modification of the film growth conditions(these modifications can be measured and compared via the sound velocityof the piezoelectric films). These growth conditions can includenucleation conditions and piezoelectric layer conditions. The nucleationconditions can include temperature, thickness, growth rate, gas phaseratio (V/III), and the like. The piezo electric layer conditions caninclude transition conditions from the nucleation layer, growthtemperature, layer thickness, growth rate, gas phase ratio (V/III), postgrowth annealing, and the like. Further details of the present methodcan be found below.

FIG. 17 is a simplified graph illustrating the results of forming apiezoelectric layer for an acoustic resonator device according to anexample of the present invention. This graph highlights the ability ofto tailor the acoustic properties of the material for a given Aluminummole fraction. Referring to step 1607 above, such flexibility allows forthe resulting resonator properties to be tailored to the individualapplication. As shown, graph 1700 depicts a plot of acoustic velocity(m/s) over aluminum mole fraction (%). The marked region 1720 shows themodulation of acoustic velocity via strain engineering of the piezoelectric layer at an aluminum mole fraction of 0.4. Here, the data showsthat the change in acoustic velocity ranges from about 7,500 m/s toabout 9,500 m/s, which is about ±1,000 m/s around the initial acousticvelocity of 8,500 m/s. Thus, the modification of the growth parametersprovides a large tunable range for acoustic velocity of the acousticresonator device. This tunable range will be present for all aluminummole fractions from 0 to 1.0 and is a degree of freedom not present inother conventional embodiments of this technology.

The present method also includes strain engineering by impurityintroduction, or doping, to impact the rate at which a sound wave willpropagate through the material. Referring to step 1607 above, impuritiescan be specifically introduced to enhance the rate at which a sound wavewill propagate through the material. In an example, the impurity speciescan include, but is not limited to, the following: silicon (Si),magnesium (Mg), carbon (C), oxygen (O), erbium (Er), rubidium (Rb),strontium (Sr), scandium (Sc), beryllium (Be), molybdenum (Mo),zirconium (Zr), Hafnium (Hf), and vanadium (Va). Silicon, magnesium,carbon, and oxygen are common impurities used in the growth process, theconcentrations of which can be varied for different piezoelectricproperties. In a specific example, the impurity concentration rangesfrom about 1 E+10 to about 1 E+21 per cubic centimeter. The impuritysource used to deliver the impurities to can be a source gas, which canbe delivered directly, after being derived from an organometallicsource, or through other like processes.

The present method also includes strain engineering by the introductionof alloying elements, to impact the rate at which a sound wave willpropagate through the material. Referring to step 1607 above, alloyingelements can be specifically introduced to enhance the rate at which asound wave will propagate through the material. In an example, thealloying elements can include, but are not limited to, the following:magnesium (Mg), erbium (Er), rubidium (Rb), strontium (Sr), scandium(Sc), titanium (Ti), zirconium (Zr), Hafnium (Hf), vanadium (Va),Niobium (Nb), and tantalum (Ta). In a specific embodiment, the alloyingelement (ternary alloys) or elements (in the case of quaternary alloys)concentration ranges from about 0.01% to about 50%. Similar to theabove, the alloy source used to deliver the alloying elements can be asource gas, which can be delivered directly, after being derived from anorganometallic source, or through other like processes. Those ofordinary skill in the art will recognize other variations,modifications, and alternatives to these processes.

The methods for introducing impurities can be during film growth(in-situ) or post growth (ex-situ). During film growth, the methods forimpurity introduction can include bulk doping, delta doping, co-doping,and the like. For bulk doping, a flow process can be used to create auniform dopant incorporation. For delta doping, flow processes can beintentionally manipulated for localized areas of higher dopantincorporation. For co-doping, the any doping methods can be used tosimultaneously introduce more than one dopant species during the filmgrowth process. Following film growth, the methods for impurityintroduction can include ion implantation, chemical treatment, surfacemodification, diffusion, co-doping, or the like. The of ordinary skillin the art will recognize other variations, modifications, andalternatives.

FIG. 18A is a simplified diagram illustrating a method for forming apiezoelectric layer for an acoustic resonator device according to anexample of the present invention. As shown in device 1801, thepiezoelectric layer 1831, or film, is directly grown on the nucleationlayer 1821, which is formed overlying a surface region of a substrate1810. The nucleation layer 1821 may be the same or different atomiccomposition as the piezoelectric layer 1831. Here, the piezoelectricfilm 1831 may be doped by one or more species during the growth(in-situ) or post-growth (ex-situ) as described previously.

FIG. 18B is a simplified diagram illustrating a method for forming apiezoelectric layer for an acoustic resonator device according to anexample of the present invention. As shown in device 1802, thepiezoelectric layer 1832, or film, is grown on a super latticenucleation layer 1822, which is comprised of layer with alternatingcomposition and thickness. This super lattice layer 1822 is formedoverlying a surface region of the substrate 1810. The strain of device1802 can be tailored by the number of periods, or alternating pairs, inthe super lattice layer 1822 or by changing the atomic composition ofthe constituent layers. Similarly, the piezoelectric film 1832 may bedoped by one or more species during the growth (in-situ) or post-growth(ex-situ) as described previously.

FIG. 18C is a simplified diagram illustrating a method for forming apiezoelectric layer for an acoustic resonator device according to anexample of the present invention. As shown in device 1803, thepiezoelectric layer 1833, or film, is grown on graded transition layers1823. These transition layers 1823, which are formed overlying a surfaceregion of the substrate 1810, can be used to tailor the strain of device1803. In an example, the alloy (binary or ternary) content can bedecreased as a function of growth in the growth direction. This functionmay be linear, step-wise, or continuous. Similarly, the piezoelectricfilm 1833 may be doped by one or more species during the growth(in-situ) or post-growth (ex-situ) as described previously.

In an example, the present invention provides a method for manufacturingan acoustic resonator device. As described previously, the method caninclude a piezoelectric film growth process such as a direct growth upona nucleation layer, growth upon a super lattice nucleation layer, or agrowth upon graded transition nucleation layers. Each process can usenucleation layers that include, but are not limited to, materials oralloys having at least one of the following: AlN, AlGaN, GaN, InN,InGaN, AlInN, AlInGaN, and BN. Those of ordinary skill in the art willrecognize other variations, modifications, and alternatives.

One or more benefits are achieved over pre-existing techniques using theinvention. In particular, the present device can be manufactured in arelatively simple and cost effective manner while using conventionalmaterials and/or methods according to one of ordinary skill in the art.Using the present method, one can create a reliable single crystal basedacoustic resonator using multiple ways of three-dimensional stackingthrough a wafer level process. Such filters or resonators can beimplemented in an RF filter device, an RF filter system, or the like.Depending upon the embodiment, one or more of these benefits may beachieved. Of course, there can be other variations, modifications, andalternatives.

In an example, the present invention provides for methods ofmanufacturing acoustic resonator or filter devices using modificationsto production conditions, process conditions, and perimeter structuremodifications. FIGS. 19A-44D describe specific examples of suchmanufacturing methods using a combination of top views, cross-sectionalviews, and close-up of device portions. Throughout these figures, unlessotherwise stated, the first two digits of any numbering of deviceelements corresponds to the figure number, while the last two digits, orthe last two digits supplemented by a hyphenated number, of anynumbering of device elements correspond to the same device elementacross all figures (e.g., 1920, 2020, and 2120 all refer to thepiezoelectric layer).

FIG. 19A is a simplified diagram illustrating a top view of an acousticresonator device according to an example of the present invention. Asshown, device 1901 shows a topside metal electrode 1930 and a backsidemetal electrode 1970 formed on opposite sides of a piezoelectric layer1920 (not shown), which is formed overlying a substrate 1910. Here, thepiezoelectric layer 1920 is omitted to show the relative spatialpositions of the device elements, but the piezoelectric layer 1920 isshown below in FIG. 19B. Both the topside metal electrode 1930 and thebackside metal electrode 1970 are electrically coupled to one or moremetal pads 1950. The backside metal electrode 1970 is also electricallycoupled to a topside metal plug 1941 formed within a topsidemicro-trench 1940. The topside metal plug 1941 is electrically coupledto a metal pad 1950. Also, the backside metal electrode 1970 is formedwithin a backside trench 1960, which defines the cavity side walls orbackside trench edges 1911 of substrate 1910.

FIG. 19B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 19A. Here, device 1902 showsthe same device elements as described for device 1901 along the A-A′dotted line in FIG. 19A. FIGS. 19A and 19B provide a foundation todiscuss the modifications found in FIGS. 20A-27B. As an additional note,any of the resonator/filters described above and below may containvarious passivation layers that can serve as a temperature compensationlayer or any other dielectric layer. These passivation layers can beused to protect the topside and backside electrodes and can comprisesilicon materials, dielectric materials, and the like and combinationsthereof.

In an example, the present invention provides a method of usingdifferent geometric shapes or geometric areas to characterize thetopside metal electrode 1930, the backside metal electrode 1970, and thebackside trench/cavity 1960. Potential benefits of forgoing restrictionof the shapes of these device elements can reduce the impact of spuriousmodes and relax constraints on process.

The different geometries can be formed by creating different geometricareas using masks to pattern the electrodes (1930, 1970) and thebackside trench 1960. These geometric areas can be patterned usingphoto-lithography, etching, and other like processes or combinationsthereof. The geometric areas can include polygonal shapes having ‘n’sides, where ‘n’ is greater than or equal to three. In specificexamples, these geometric areas can include skewed or regular polygonalshapes having parallel or non-parallel edges. In other cases, thegeometric area can include a circle, an ellipses, non-polygonal shapes,skew non-polygonal shapes, or irregular shapes, or any other shape.These geometric areas can be characterized as having similar ordissimilar shapes. In a specific example, the area ratio between thegeometric areas of the topside metal electrode and the backside metalelectrode can be between about 0.1 to about 10. Also, the geometricareas of the electrodes and the backside trench can be spatiallyconfigured such that the distance between either the topside metalelectrode or the backside metal electrode and any of the backside trenchedges is between about 0.1 microns and about 500 microns. The deviceelements, methods, and techniques described above can be combined withany device elements, methods, and techniques described in the followingfigures. Those of ordinary skill in the art will recognize othervariations, modifications, and alternatives.

FIG. 20A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with electrode boundary modificationsaccording to an example of the present invention. As shown, device 2001depicts a topside metal electrode 2031 formed with modified edges. Thismethod can also be applied to the backside or both the topside andbackside.

FIGS. 20B through 20G are simplified diagrams illustratingcross-sectional views of portions of acoustic resonator devices withelectrode boundary modifications according to an example of the presentinvention. In each of the following examples, the electrode edge profilemodifications can be implemented on the topside electrode, the backsideelectrode, or both. Different metal and dielectric materials may also beused. In FIG. 20B, device 2002 includes a top metal electrode 2031 and abottom metal electrode 2071 with “down slope” edges. In FIG. 20C, device2003 includes a top metal electrode 2033 and a bottom metal electrode2073 with “up slope” edges. In FIG. 20D, device 2004 includes a topmetal electrode 2034 and a bottom metal electrode 2074 with “up and downslope” edges. In FIG. 20E, device 2005 includes a top metal electrode2035 and a bottom metal electrode 2075 with “up-flat and down slope”edges. In FIG. 20F, device 2006 includes a top metal electrode 2036 anda bottom metal electrode 2076 with “stair steps” edges. In FIG. 20G,device 2007 includes a top metal electrode 2037 and a bottom metalelectrode 2077 with “circular” edges. Other shapes may be used as well.

In an example, the present invention provides a method of modifying theedges of the metal electrodes or resonator using additive and/orsubtractive processes to achieve a desired profile at the resonator orelectrode boundary. This can also include tapering or shaping theresonator boundary and using an ion implantation process at theboundary. Also, the present method can include forming a desired gapbetween the substrate and the electrodes and configuring a desiredrelative enclosure between the top and bottom electrodes. These methodscan be used singly or in combination to increase the energy content of adesired mode. Other potential benefits include, among others, increasedQ factor and the ability to reduce mask levels or process steps comparedto other methods of spurious mode suppression.

In a specific example, standard multiple photolithography and etchingprocesses can be used to realized the patterns in the electrode metals.The desired profile of the electrode edge can be achieved by build-up orremoval approaches using traditional layer deposition methods, such assputtering, evaporating, printing, or the like, followed by dry or wetetching of the electrode metal with specific masking layers to achievethe desired ratio or removal rates. Such processes can be used to formtapered profiles. Additive processes can involve deposition processessuch as patterned sputtering, patterned evaporation and lift-off,evaporation and patterned etch, and the like. Subtractive processes caninclude involve blanket deposition and non-masked removal processes suchas laser ablation, ion beam milling, or the like. The device elements,methods, and techniques described above can be combined with any deviceelements, methods, and techniques described in the following figures.Those of ordinary skill in the art will recognize other variations,modifications, and alternatives.

FIG. 21A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with grooved electrode boundarymodifications according to an example of the present invention. FIG. 21Ais similar to FIG. 20A with the addition of a groove formed within avicinity of the electrode edges. In each of the following examples, themodifications can be implemented on the topside electrode, the backsideelectrode, or both. Different metal and dielectric materials may also beused.

FIGS. 21B through 21G are simplified diagrams illustratingcross-sectional views of portions of acoustic resonator devices withgrooved electrode boundary modifications according to an example of thepresent invention. Each of these figures shows the same edge profilesshapes with the addition of the groove formed near the edge. In FIG.21B, device 2102 includes a top metal electrode 2131 and a bottom metalelectrode 2171 with grooved “down slope” edges. In FIG. 21C, device 2103includes a top metal electrode 2133 and a bottom metal electrode 2173with grooved “up slope” edges. In FIG. 21D, device 2104 includes a topmetal electrode 2134 and a bottom metal electrode 2174 with grooved “upand down slope” edges. In FIG. 21E, device 2105 includes a top metalelectrode 2135 and a bottom metal electrode 2175 with grooved “up-flatand down slope” edges. In FIG. 21F, device 2106 includes a top metalelectrode 2136 and a bottom metal electrode 2176 with grooved “stairsteps” edges. In FIG. 21G, device 2107 includes a top metal electrode2137 and a bottom metal electrode 2177 with grooved “circular” edges.Other shapes may be used as well. The device elements, methods, andtechniques described above can be combined with any device elements,methods, and techniques described in the following figures. Those ofordinary skill in the art will recognize other variations,modifications, and alternatives.

FIG. 22A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with a grooved piezoelectric layeraccording to an example of the present invention. As shown, thepiezoelectric layer 2221 of device 2201 has grooves formed within avicinity or the electrode edges. In each of the following examples, themodifications can be implemented on the topside of the piezoelectriclayer, the backside of the piezoelectric layer, or both.

FIGS. 22B and 22C are simplified diagrams illustrating cross-sectionalviews of portions of acoustic resonator devices with groovedpiezoelectric layers according to an example of the present invention.FIG. 22B shows an example with single grooves formed on both the topsideand backside of the piezoelectric layer 2222. FIG. 22C shows an examplewith double grooves formed on both the topside and backside of thepiezoelectric layer 2223. The device elements, methods, and techniquesdescribed above can be combined with any device elements, methods, andtechniques described in the following figures. Those of ordinary skillin the art will recognize other variations, modifications, andalternatives.

FIG. 23A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with a grooved piezoelectric sub-surfacelayer according to an example of the present invention. As shown, thetopside metal electrode 2331 of device 2301 is formed within a groove orcavity within the piezoelectric layer 2321. In each of the followingexamples, the modifications can be implemented on the topside of thepiezoelectric layer, the backside of the piezoelectric layer, or both.

FIGS. 23B and 23C are simplified diagrams illustrating cross-sectionalviews of portions of acoustic resonator devices with groovedpiezoelectric sub-surface layers according to an example of the presentinvention. FIG. 23B shows an example with both topside and backsidegrooves in the piezoelectric layer 2322. FIG. 23C shows the combinationof topside and backside grooves and an additional groove formed on eachside within a vicinity of the edge of the topside and backside grooves.The device elements, methods, and techniques described above can becombined with any device elements, methods, and techniques described inthe following figures. Those of ordinary skill in the art will recognizeother variations, modifications, and alternatives.

FIG. 24A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with electrode edge border materialsaccording to an example of the present invention. As shown, device 2401shows the use of edge border materials 2441 formed within a vicinity oradjacent to the top metal electrode 2430. In each of the followingexamples, the modifications can be implemented on the topside of thepiezoelectric layer, the backside of the piezoelectric layer, or both.

FIGS. 24B through 24E are simplified diagrams illustratingcross-sectional views of portions of acoustic resonator devices withelectrode edge border materials according to an example of the presentinvention. FIG. 24B shows an example of using topside and backside edgeborder materials 2441. FIG. 24C shows an example of additionally forminggrooves in the electrode 2433 adjacent to the edge border material 2441.FIG. 24D shows an example of edge border materials 2444 that overlap theelectrode. FIG. 24E shows an example of only using backside electrodeedge border materials 2441. The device elements, methods, and techniquesdescribed above can be combined with any device elements, methods, andtechniques described in the following figures. Those of ordinary skillin the art will recognize other variations, modifications, andalternatives.

FIGS. 25A through 25D are simplified diagrams illustratingcross-sectional views of a an acoustic resonator device subjected to anion implantation process according to an example of the presentinvention. As described previously, ion implantation processes can beused to increase the energy content of a desired mode. Masked ionimplantation involving depositing a masking material and selectivelyremoving portions of that material via photo lithography and etchingsteps. The ion implantation of specific species can be used to achievedesired piezoelectric coefficient parameter values need for the desiredk2. In each of the following examples, the modifications can beimplemented on the topside of the piezoelectric layer, the backside ofthe piezoelectric layer, or both.

FIG. 25A shows an example in which the ion implantation process is usedbefore the formation of the top metal electrode. FIG. 25B shows anexample in which the ion implantation process is used after theformation of the top metal electrode. FIG. 25C shows an example in whichthe ion implantation process is used before the formation of thebackside metal electrode, while FIG. 25D shows an example in which theion implantation process is used after the formation of the backsidemetal electrode. In the latter two figures, the device is mounted on atemporary carrier 2590 by using a temporary adhesive 2580. In a specificexample, the masked ion implantation process can be bounded to a zonecharacterized by 500 um outside the central resonator area, wherein thezone extends from and includes the central resonator area. Thisimplantation process can also be characterized by a dosage between 1E+14 and 1 E+20 ions per cubic centimeter. Also, this process can useone or more of the following species: H, He, B, C, O, Fe, Mo, Ta, W, orother transition metal or combinations thereof. The device elements,methods, and techniques described above can be combined with any deviceelements, methods, and techniques described in the following figures.Those of ordinary skill in the art will recognize other variations,modifications, and alternatives.

FIG. 26A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with spatial modifications according to anexample of the present invention. As shown, device 2601 addresses thespecific dimensions of the cavity sidewall or backside trench sidewallgap and enclosure distance of the backside metal electrode compared tothe topside metal electrode. These modifications can potentially improveall resonator performance metrics. In each of the following examples,the modifications can be implemented on the topside of the piezoelectriclayer, the backside of the piezoelectric layer, or both.

FIGS. 26B through 26E are simplified diagrams illustratingcross-sectional views of portions of acoustic resonator devices withspatial modifications according to an example of the present invention.FIG. 26B shows an example of forming device 2602 with the sidewall gapdistance of x₁. In a specific example, the distance x₁ can range fromabout 0.1 um to about 500 um. The device elements, methods, andtechniques described above can be combined with any device elements,methods, and techniques described in the following figures. Those ofordinary skill in the art will recognize other variations,modifications, and alternatives.

FIG. 26C shows the combination of the sidewall gap with the electrodeedge profile shaping described earlier. FIG. 26D shows an example offorming the device 2604 such that the backside contact or metalelectrode 2670 is larger than the topside contact or metal electrode2630 with an overlap distance of x₂. In a specific example, x₂ can rangefrom about 0.1 um to about 500 um. The device elements, methods, andtechniques described above can be combined with any device elements,methods, and techniques described in the following figures. Those ofordinary skill in the art will recognize other variations,modifications, and alternatives.

FIG. 27A is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device according to an example of the presentinvention. This figure, similar to FIG. 19A, is considered a seriesresonator and is used as comparison for FIG. 27B below.

FIG. 27B is a simplified diagram illustrating a cross-sectional view ofan acoustic resonator device with frequency offset structure accordingto an example of the present invention. As shown, device 2702 includesforming additional frequency offset structure electrode layerselectrically coupled to the topside metal electrode 2730, the backsidemetal electrode 2770, or both. This forms a shunt resonator. In aspecific example, the frequency offset structure layers can includemetals and materials such as Mo, Al, W, Ru, AlN, SiN, or SiO₂. Thedevice elements, methods, and techniques described above can be combinedwith any device elements, methods, and techniques described in thefollowing figures. Those of ordinary skill in the art will recognizeother variations, modifications, and alternatives.

FIG. 28A is a simplified diagram illustrating a top view of a multipleacoustic resonator device according to an example of the presentinvention. As shown, device 2801 includes three separate resonators,each having a topside (2831, 2832, 2833) and backside (2871, 2872, 2873)metal electrodes. Each of the topside metal electrodes are coupled to ametal pad 2850 extending away from the backside trench 2860 and all ofthe topside metal electrodes are coupled together by another metal pad2850.

FIG. 28B is a simplified diagram illustrating a cross-sectional view ofthe multiple acoustic resonator device shown in FIG. 28A. The deviceelements, methods, and techniques described above can be combined withany device elements, methods, and techniques described in the followingfigures. Those of ordinary skill in the art will recognize othervariations, modifications, and alternatives.

FIG. 29A is a simplified diagram illustrating a top view of a multipleacoustic resonator device according to an example of the presentinvention. As shown, device 2901 includes the same three separateresonators, each having a topside (2931, 2932, 2933) and backside (2971,2972, 2973) metal electrodes. Here, each of the topside metal electrodesare electrically coupled to metal pads 2950 that are electricallycoupled to vias 2951 within the backside cavity region.

FIG. 29B is a simplified diagram illustrating a cross-sectional view ofthe multiple acoustic resonator device shown in FIG. 29A. The deviceelements, methods, and techniques described above can be combined withany device elements, methods, and techniques described in the followingfigures. Those of ordinary skill in the art will recognize othervariations, modifications, and alternatives.

FIG. 30A is a simplified diagram illustrating a top view of an acousticresonator device according to an example of the present invention. FIG.30A is similar to FIG. 19A except that the connections between thetopside metal electrode 3030 and one of the metal pads 3050 and betweenthe backside metal electrode 3070 and another of the metal pages 3050are not spatially configured within the same horizontal plane. Thetopside connection (TC) is marked by region 3039, while the backsideconnection (BC) is marked by region 3079. Although this figure showsthis particular offset configuration, the present invention contemplatesthat the TC and BC connection regions can be configured along any edgeof the topside and backside metal electrodes, respectively. In each ofthe following examples, the modifications can be implemented on thetopside of the piezoelectric layer, the backside of the piezoelectriclayer, or both.

FIG. 30B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 30A. A dotted line separatesdevice portion 3002 (as defined by portion 3039 in FIG. 30A), whichshows the cross-section near the TC region, and device portion 3003 (asdefined by portion 3040 in FIG. 30A), which shows the cross-section nearthe BC region. The device elements, methods, and techniques describedabove can be combined with any device elements, methods, and techniquesdescribed in the following figures. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

In an example, the present invention provides several methods forimproving the resonator Q factor by various structural configurationsupon the topside, the backside, or both. As a note, the central area ofthe resonator is defined as the area of the resonator that is comprisedof the sandwich of the topside electrode, the piezoelectric layer, andthe backside electrode, where the topside and backside electrode arewithout modification. This means that that uniform area of the centralportion of the resonator, excluding the edges of the resonator where theperimeter may be modified in a variety of ways according to examples ofthe present invention. Additionally, the piezoelectric layer may referto single crystal or polycrystalline piezoelectric layers. In a specificexample, the crystalline material of the piezoelectric layer may besubstantially or essentially single crystal with a combination of singlecrystal and polycrystalline materials. In each of the followingexamples, the modifications can be implemented on the topside of thepiezoelectric layer, the backside of the piezoelectric layer, or both.

FIG. 31A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside metal perimeterstructure modifications according to an example of the presentinvention. FIG. 31A is similar to FIG. 30B with the addition of forminga topside pillar structure 3131 overlying a portion of the toppiezoelectric surface region within a vicinity of the topside metalelectrode and outside of the topside metal electrode perimeter.

In an example, the topside pillar structure 3131, as with any pillarstructure or pillar, can include a metal material, a dielectricmaterial, or a combination thereof This pillar structure 3131 can bespatially configured around the perimeter of the topside metal electrodeand can be a continuous pillar structure or comprised of one or morenon-continuous pillars. In a specific example, the topside pillarstructure includes a gap region within a vicinity of the TC region orthe BC region. In this case, the topside pillar structure comprises ametal material. Also, one or more optional backside pillars 3179 can beformed underlying a portion of the bottom piezoelectric surface region.The device 3101 can also include one or more combination electrodepillars formed overlying a portion of the topside electrode surfaceregion. The combination electrode pillars comprises a metal pillar 3133formed overlying a dielectric pillar 3134. The device 3101 can alsoinclude a topside electrode pillar structure formed overlying a portionof the topside electrode surface region and within the topside metalelectrode perimeter. The topside electrode pillar structure can bespatially configured substantially along the topside electrode perimeterand can also be a continuous pillar structure or comprise one or morenon-continuous pillars. This topside electrode pillar structure can alsoinclude a gap region within a vicinity of the TC or BC regions.

FIG. 31B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 31A. This view showsthe region near BC, which is near the micro-trench 3140. As shown,device 3102 includes the topside pillar structure 3131 and the topsideelectrode pillar structure 3132.

FIG. 31C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside metal perimeterstructure modifications according to an example of the presentinvention. As shown, device 3103 is the backside configuration of device3102 in FIG. 31B. Here, the backside metal pillar structure 3171 andbackside metal electrode pillar structure 3172 are formed near the TCregion, along with an optional topside pillar 3139.

FIG. 31D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 31C. As shown,device 3104 is the backside configuration of device 3101 in FIG. 31A.Here, the backside metal pillar structure 3171 and backside metalelectrode pillar structure 3172 are formed near the BC region, alongwith an combination backside pillar (3173, 3174). The device elements,methods, and techniques described above can be combined with any deviceelements, methods, and techniques described in the following figures.Those of ordinary skill in the art will recognize other variations,modifications, and alternatives.

FIG. 32A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside metal perimeterstructure modifications according to an example of the presentinvention. FIG. 32A is similar to FIG. 31A except the topside electrodepillar structure is omitted. The reference numerals for the elementsshown in FIG. 32A-32D match those elements shown in FIGS. 31A-31D exceptthat the FIG. 32 numerals start with the prefix “32” as opposed to theFIG. 31 numerals, which start with the prefix“31.”

FIG. 32B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 32A. FIG. 32B issimilar to FIG. 31B except the topside electrode pillar structure isomitted.

FIG. 32C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside metal perimeterstructure modifications according to an example of the presentinvention. FIG. 32C is similar to FIG. 31C except the backside electrodepillar structure is omitted.

FIG. 32D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 32C. FIG. 32D issimilar to FIG. 31D except the backside electrode pillar structure isomitted. The device elements, methods, and techniques described abovecan be combined with any device elements, methods, and techniquesdescribed in the following figures. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

FIG. 33A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric perimeterstructure modifications according to an example of the presentinvention. The reference numerals for the elements shown in FIG. 33A-33Dmatch those elements shown in FIGS. 31A-31D except that the FIG. 33numerals start with the prefix “33” as opposed to the FIG. 31 numerals,which start with the prefix“31.” As shown, device 3301 includes atopside dielectric pillar structure 3335 formed within a vicinity of thetopside electrode perimeter or adjacent to the topside metal electrode3330. Another dielectric pillar 3336 can also be formed adjacent to thetopside electrode pillar structure 3332. The optional dielectric pillar3378 is can also be formed adjacent to the backside metal electrode3370.

FIG. 33B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 33A. As shown,device 3302 includes the topside dielectric pillar structure 3335 formedadjacent to the topside metal electrode 3330.

FIG. 33C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric perimeterstructure modifications according to an example of the presentinvention. As shown, device 3303 is the backside configuration of device3302 in FIG. 33B. Here, a dielectric pillars 3338 is formed adjacent tothe topside metal electrode 3330. Further, dielectric pillars 3375 areformed adjacent to the backside metal electrode 3370.

FIG. 33D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 33C. As shown,device 3304 is the backside configuration of device 3301 in FIG. 33A.Here, a dielectric pillar 3376 can be formed underlying the backsidemetal electrode 3370 and adjacent to one of the backside metal electrodepillars 3372. The device elements, methods, and techniques describedabove can be combined with any device elements, methods, and techniquesdescribed in the following figures. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

FIG. 34A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric perimeterstructure modifications according to an example of the presentinvention. FIG. 34A is similar to FIG. 33A except the topside electrodepillar structure is omitted. The reference numerals for the elementsshown in FIG. 34A-34D match those elements shown in FIGS. 33A-33D exceptthat the FIG. 34 numerals start with the prefix “34” as opposed to theFIG. 33 numerals, which start with the prefix“33.”

FIG. 34B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 34A. FIG. 34B issimilar to FIG. 33B except the topside electrode pillar structure isomitted.

FIG. 34C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric perimeterstructure modifications according to an example of the presentinvention. FIG. 34C is similar to FIG. 34C except the backside electrodepillar structure is omitted.

FIG. 34D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 34C. FIG. 34D issimilar to FIG. 33D except the backside electrode pillar structure isomitted. The device elements, methods, and techniques described abovecan be combined with any device elements, methods, and techniquesdescribed in the following figures. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

FIG. 35A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention. As shown, device 3501 includes the topside electrode metalpillar structure 3532 and the topside combination pillar (3533, 3534)formed adjacent to the pillar structure 3532. This device 3501 alsoinclude a dielectric pillar structure 3535-1, which has an overlapportion overlying a portion of the topside metal electrode 3530, and ametal pillar structure 3531-1, which has an overlap portion overlying aportion of the dielectric pillar structure 3535-1. The optional pillarsare similarly configured with the dielectric pillar 3578-1 and metalpillar 3579-1. The reference numerals for any remaining undiscussedelements shown in FIG. 35A-35D match those elements shown in FIGS.31A-31D except that the FIG. 35 numerals start with the prefix “35” asopposed to the FIG. 31 numerals, which start with the prefix“31.”

FIG. 35B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 35A. Here, thecombination pillar structure, including dielectric pillar structure3535-1 and metal pillar structure 3531-1, are similarly configured andadjacent to the topside electrode metal pillar structure 3532.

FIG. 35C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention. As shown, device 3503 is the backside configuration of device3502 in FIG. 35B.

FIG. 35D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 35C. As shown,device 3504 is the backside configuration of device 3501 in FIG. 35A.The device elements, methods, and techniques described above can becombined with any device elements, methods, and techniques described inthe following figures. Those of ordinary skill in the art will recognizeother variations, modifications, and alternatives.

FIG. 36A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention. FIG. 36A is similar to FIG. 35A except the topside electrodepillar structure is omitted. The reference numerals for the elementsshown in

FIG. 36A-36D match those elements shown in FIGS. 35A-35D except that theFIG. 36 numerals start with the prefix “36” as opposed to the FIG. 35numerals, which start with the prefix“35.”

FIG. 36B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 36A. FIG. 36B issimilar to FIG. 35B except the topside electrode pillar structure isomitted.

FIG. 36C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention. FIG. 36C is similar to FIG. 35C except the backside electrodepillar structure is omitted.

FIG. 36D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 36C. FIG. 36D issimilar to FIG. 35D except the backside electrode pillar structure isomitted. The device elements, methods, and techniques described abovecan be combined with any device elements, methods, and techniquesdescribed in the following figures. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

FIG. 37A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention. As shown, device 3701 includes a combination pillar structurewith a dielectric pillar structure 3735-1 with an overlying metal pillarstructure 3731-2. Here, the metal pillar structure 3731-2 does notoverlap the dielectric pillar structure 3735-1. The reference numeralsfor any remaining undiscussed elements shown in FIG. 37A-37D match thoseelements shown in FIGS. 35A-35D except that the FIG. 37 numerals startwith the prefix “37” as opposed to the FIG. 35 numerals, which startwith the prefix“35.”

FIG. 37B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 37A. As shown,device 3702 includes a combination pillar, including dielectric pillar3734 with an overlying metal pillar 3733, formed overlying a portion ofthe topside metal electrode 3730.

FIG. 37C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention. As shown, device 3703 is the backside configuration of device3702 in FIG. 37B.

FIG. 37D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 37C. As shown,device 3704 is the backside configuration of device 3701 in FIG. 37A.The device elements, methods, and techniques described above can becombined with any device elements, methods, and techniques described inthe following figures. Those of ordinary skill in the art will recognizeother variations, modifications, and alternatives.

FIG. 38A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention. FIG. 38A is similar to FIG. 35A except that the topside metalpillar structure 3831-3 does not overlap dielectric pillar structure3835-1, which overlaps a portion of the topside metal electrode 3830.The reference numerals for any remaining undiscussed elements shown inFIG. 38A-38D match those elements shown in FIGS. 35A-35D except that theFIG. 38 numerals start with the prefix “38” as opposed to the FIG. 35numerals, which start with the prefix“35.”

FIG. 38B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 38A. FIG. 38B issimilar to FIG. 35B except topside metal pillar structure 3831-3 doesnot overlap dielectric pillar structure 3835-1, which overlaps a portionof the topside metal electrode 3830.

FIG. 38C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention. As shown, device 3803 is the backside configuration of device3802 in FIG. 38B.

FIG. 38D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 38C. As shown,device 3804 is the backside configuration of device 3801 in FIG. 38A.The device elements, methods, and techniques described above can becombined with any device elements, methods, and techniques described inthe following figures. Those of ordinary skill in the art will recognizeother variations, modifications, and alternatives.

FIG. 39A is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with topside dielectric and metalperimeter structure modifications according to an example of the presentinvention. FIG. 39A is similar to FIG. 38A except the topside electrodepillar structure is omitted. The reference numerals for any elementsshown in FIG. 39A-39D match those elements shown in FIGS. 38A-38D exceptthat the FIG. 39 numerals start with the prefix “39” as opposed to theFIG. 38 numerals, which start with the prefix“3 8.”

FIG. 39B is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 39A. FIG. 39B issimilar to FIG. 38B except the topside electrode pillar structure isomitted.

FIG. 39C is a simplified diagram illustrating a first cross-sectionalview of an acoustic resonator device with backside dielectric and metalperimeter structure modifications according to an example of the presentinvention. FIG. 39C is similar to FIG. 38C except the backside electrodepillar structure is omitted.

FIG. 39D is a simplified diagram illustrating a second cross-sectionalview of the acoustic resonator device shown in FIG. 39C. FIG. 39D issimilar to FIG. 39D except the backside electrode pillar structure isomitted. The device elements, methods, and techniques described abovecan be combined with any device elements, methods, and techniquesdescribed in the following figures. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

FIG. 40A is a simplified diagram illustrating a top view of an acousticresonator device with subsurface modifications according to an exampleof the present invention. FIG. 40A is similar to FIG. 30A except thatthe piezoelectric layer 4020 has grooves formed on the topside andbackside. The topside metal electrode 4030 is formed partially withinthe topside piezoelectric groove, while the backside metal electrode4070 is formed partially without the backside piezoelectric groove. Thegrooves are shown by the dotted line region 4021/4022.

FIG. 40B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 40A. The piezoelectricgrooves described previously can be seen clearly here, marked by region4021 and 4022. The device elements, methods, and techniques describedabove can be combined with any device elements, methods, and techniquesdescribed in the following figures. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

FIG. 41A is a simplified diagram illustrating a top view of an acousticresonator device with perimeter structure modifications according to anexample of the present invention. As shown, device 4101 includes atopside energy confinement structure 4190 formed around or adjacent tothe topside metal electrode 4130. This energy confinement structure 4190includes at least one portion removed to form a structure break region.Although one break region is shown here, the energy confinementstructure 4190 can have multiple break regions. This device 4101 alsoincludes a topside sandbar structure 4191 overlying the toppiezoelectric surface region within a vicinity of the topside structurebreak region. Here, the sandbar structure 4191 is offset outside of theperimeter of the energy confinement structure 4190. In a specificexample, the topside sandbar structure can be spatially configured witha gap distance of about 0.1 um to about 100 um to the topside metalelectrode 4130. In each of the following examples, the modifications canbe implemented on the topside of the piezoelectric layer, the backsideof the piezoelectric layer, or both.

FIG. 41B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 41A. Device 4102 shows theoffset of the sandbar structure 4191 from the energy confinementstructure 4190. The device elements, methods, and techniques describedabove can be combined with any device elements, methods, and techniquesdescribed in the following figures. Those of ordinary skill in the artwill recognize other variations, modifications, and alternatives.

FIG. 42 is a simplified diagram illustrating a top view of an acousticresonator device with perimeter structure modifications according to anexample of the present invention. FIG. 42 is similar to FIG. 41A exceptthat the sandbar structure 4291-1 is curved. Other shapes can also beused, including an oppositely curved structure, an angled structure, orothers.

FIG. 43 is a simplified diagram illustrating a top view of an acousticresonator device with perimeter structure modifications according to anexample of the present invention. As shown, device 4300 includes anenergy confinement structure 4390 with a combination of materials. Theenergy confinement structure 4390 can comprise dielectric materials,metal materials, or combinations thereof. Here, the dielectric portionsare marked as item 4390-1 and the metal portions are marked as item4390-2.

FIG. 44A is a simplified diagram illustrating a top view of an acousticresonator device with perimeter structure modifications according to anexample of the present invention. As shown, device 4401 includes anenergy confinement structure configured with a castellation pattern 4492characterized with repeated castellation shape. This castellation shapecan include a square, triangle, a polygonal shape, a non-polygonalshape, or other shape.

FIG. 44B is a simplified diagram illustrating a cross-sectional view ofthe acoustic resonator device shown in FIG. 44A. As shown, device 4402includes the castellation-patterned energy confinement structure ashorter castellation pattern 4492-1 and a taller castellation pattern4492-2. The height of the repeating castellation pattern can vary acrossdifferent examples.

FIG. 44C is a simplified diagram illustrating a cross-sectional view ofa portion of the acoustic resonator device shown in FIGS. 44A and 44B.Device 4403 shows an example castellation pattern in which thehorizontal portion is twice the distance of the vertical portion,denoted by ‘d.’ The length and height ratios of the repeatingcastellation patterns can vary across different examples. This figurealso shows the relative height of the castellation pattern 4492-1 to thetopside metal electrode 4430, shown in dotted lines.

FIG. 44D is a simplified diagram illustrating a cross-sectional view ofa portion of the acoustic resonator device shown in FIGS. 44A and 44B.This figure shows the relative height of the castellation pattern 4492-2to the topside metal electrode 4430, shown in dotted lines. The deviceelements, methods, and techniques described above can be combined withany device elements, methods, and techniques described in the followingfigures. Those of ordinary skill in the art will recognize othervariations, modifications, and alternatives.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the piezoelectric layer having a toppiezoelectric surface region and a bottom piezoelectric surface region;forming a topside metal electrode overlying the top piezoelectricsurface region, the topside metal electrode being characterized by atopside electrode geometric area; forming a topside micro-trench withina portion of the single crystal piezoelectric layer; forming a topsidemetal having a topside metal plug within the topside micro-trench;forming a backside trench within the substrate exposing the bottompiezoelectric surface region, the backside trench underlying the topsidemetal electrode and the topside micro-trench, the backside trench beingcharacterized by a cavity geometric area and having one or more backsidetrench edges; forming a backside metal electrode underlying or inproximity of the bottom piezoelectric surface region within the backsidetrench, the backside metal electrode being electrically coupled to thetopside metal, the backside metal electrode being characterized by abackside electrode geometric area; forming at least two metal pads forelectrical connections, wherein at least one metal pad is electricallycoupled to the topside metal electrode, and at least one metal pad iselectrically coupled to the backside metal electrode; forming a backsidemetal plug underlying the bottom piezoelectric surface region within thebackside trench, the backside metal plug being electrically coupled tothe topside metal plug and the backside metal electrode, wherein thetopside micro-trench, the topside metal plug, and the backside metalplug form a micro-via; and wherein an area ratio between the topsideelectrode geometric area and the backside electrode geometric area isbetween about 0.1 to about 10.

In an example, each of the topside electrode geometric area, thebackside electrode geometric area, and the cavity geometric areaincludes a polygonal shape having n sides, where n is greater than orequal to three. In an example, each of the topside electrode geometricarea, the backside electrode geometric area, and the cavity geometricarea includes a skewed or regular polygonal shape having parallel ornon-parallel edges. In an example, each of the topside electrodegeometric area, the backside electrode geometric area, and the cavitygeometric area includes a circle, an ellipses, skew non-polygonalshapes, or irregular shapes; wherein the topside electrode geometricarea, the backside electrode geometric area, and the cavity geometricarea can be characterized by geometric areas having similar ordissimilar shapes. In an example, the topside electrode geometric area,the backside electrode geometric area, and the cavity geometry arespatially configured such that the distance between either the topsidemetal electrode or the backside metal electrode and any of the one ormore backside trench edges is between about 0.1 microns and about 500microns. According to an example, the present invention can provide thedevice structure resulting from the method described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the single crystal piezoelectric layer havinga top piezoelectric surface region and a bottom piezoelectric surfaceregion; forming a topside metal electrode overlying the toppiezoelectric surface region, the topside metal electrode having one ormore topside metal electrode edges being characterized by a topsideelectrode edge geometric shape; forming a topside micro-trench within aportion of the single crystal piezoelectric layer; forming a topsidemetal having a topside metal plug within the topside micro-trench;forming a backside trench within the substrate exposing the bottompiezoelectric surface region, the backside trench underlying the topsidemetal electrode and the topside micro-trench; forming a backside metalelectrode underlying or in proximity of the bottom piezoelectric surfaceregion within the backside trench, the backside metal electrode beingelectrically coupled to the topside metal, the backside metal electrodehaving one or more backside metal electrode edges being characterized bya backside electrode edge geometric shape; forming at least two metalpads for electrical connections, wherein at least one metal pad iselectrically coupled to the topside metal electrode, and at least onemetal pad is electrically coupled to the backside metal electrode; andforming a backside metal plug underlying the bottom piezoelectricsurface region within the backside trench, the backside metal plug beingelectrically coupled to the topside metal plug and the backside metalelectrode, wherein the topside micro-trench, the topside metal plug, andthe backside metal plug form a micro-via.

In an example, forming the topside metal electrode and the backsidemetal electrode includes an edge profile fabrication process to form theone or more topside metal electrode edges, wherein the edge profilefabrication process can be selected from the following: a patternedsputtering process, a patterned evaporation and lift-off process, anevaporation and patterned etching process, a trimming process, a laserablation process, and an ion beam milling process. In an example, thetopside electrode edge geometric shape includes one of the followingshapes: a down slope edge, an up slope edge, an up and down slope edge,an up-flat-down slope edge, a stair steps edge, and a circular edge. Inan example, forming the topside metal electrode includes forming thetopside metal electrode such that topside electrode edge geometric shapeis spatially configured above or within the top piezoelectric surfaceregion. In an example, the topside metal electrode includes a grooveformed within the topside metal electrode within a vicinity of the oneor more topside electrode edges. In an example, the backside electrodeedge geometric shape includes one of the following shapes: a down slopeedge, an up slope edge, an up and down slope edge, an up-flat-down slopeedge, a stair steps edge, and a circular edge. In an example, thebackside metal electrode includes a groove formed within the backsidemetal electrode within a vicinity of the one or more backside electrodeedges. In an example, forming the backside metal electrode includesforming the backside metal electrode such that backside electrode edgegeometric shape is spatially configured within or below the bottompiezoelectric surface region.

In an example, each of the topside electrode edge geometric shape andthe backside electrode edge shape includes one of the following shapes:a down slope edge, an up slope edge, an up and down slope edge, anup-flat-down slope edge, a stair steps edge, and a circular edge;wherein the topside metal electrode includes a groove formed within thetopside metal electrode within a vicinity of the one or more topsideelectrode edges; and wherein the backside metal electrode includes agroove formed within the backside metal electrode within a vicinity ofthe one or more backside electrode edges. In an example, the methodfurther includes removing a portion of the piezoelectric layer to form afirst topside groove on the top piezoelectric surface region. In anexample, the first topside groove is spatially configured overlying thebackside trench. In an example, the method further includes removing aportion of the piezoelectric layer to form a second topside groove onthe top piezoelectric surface region; wherein the second topside grooveis spatially configured within the vicinity of an edge of the topsidemetal electrode and the first groove. In an example, the first topsidegroove is spatially configured overlying a portion of the backsidetrench and the second topside groove is spatially configured overlying aportion of the substrate. In an example, the method further includesremoving a portion of the piezoelectric layer to form a first backsidegroove on the bottom piezoelectric surface region. In an example, thefirst backside groove is spatially configured within the backsidetrench. In an example, the method further includes removing a portion ofthe piezoelectric layer to form a second backside groove on the bottompiezoelectric surface region; wherein the second backside groove isspatially configured within the vicinity of an edge of the backsidemetal electrode and the first backside groove. In an example, the firstbackside groove is spatially configured within a portion of the backsidetrench and the second backside groove is spatially configured within aportion of the backside trench.

In an example, the method further includes removing a portion of thepiezoelectric layer to form a first topside groove on the toppiezoelectric surface region; and removing a portion of thepiezoelectric layer to form a first backside groove on the bottompiezoelectric surface region. In an example, the method further includesremoving a portion of the single crystal piezoelectric layer to form atopside groove on the top piezoelectric surface region; and whereinforming the topside metal electrode includes forming the topside metalelectrode overlying the top piezoelectric surface region within thetopside groove. In an example, the present method further includesremoving a portion of the single crystal piezoelectric layer to form abackside groove on the bottom piezoelectric surface region; and whereinforming the backside metal electrode includes forming the backside metalelectrode underlying the bottom piezoelectric surface region within thebackside groove. In an example, the method further includes removing aportion of the single crystal piezoelectric layer to form a topsidegroove on the top piezoelectric surface region; wherein forming thetopside metal electrode includes forming the topside metal electrodeoverlying the top piezoelectric surface region within the topsidegroove; removing a portion of the single crystal piezoelectric layer toform a backside groove on the bottom piezoelectric surface region; andwherein forming the backside metal electrode includes forming thebackside metal electrode underlying the bottom piezoelectric surfaceregion within the backside groove.

In an example, the method further includes forming a topside edge bordermaterial overlying and physically coupled to a portion of the toppiezoelectric surface region and physically coupled to a portion of thetopside metal electrode. In an example, the topside edge border materialincludes a metal material or a dielectric material. In an example,forming the topside edge border material includes forming the topsideedge border material overlying a portion of the topside metal electrode.In an example, the method further includes removing a portion of thetopside metal electrode within a vicinity of the topside edge bordermaterial to form a topside electrode groove. In an example, the methodfurther includes forming a backside edge border material underlying andphysically coupled to a portion of the bottom piezoelectric surfaceregion and physically coupled to a portion of the backside metalelectrode. In an example, the backside edge border material includes ametal material or a dielectric material. In an example, forming thebackside edge border material includes forming the backside edge bordermaterial overlying a portion of the backside metal electrode. In anexample, the method further includes removing a portion of the backsidemetal electrode within a vicinity of the backside edge border materialto form a backside electrode groove. In an example, the method furtherincludes forming an topside edge border material overlying andphysically coupled to a portion of the top piezoelectric surface regionand physically coupled to a portion of the topside metal electrode; andforming an backside edge border material underlying and physicallycoupled to a portion of the bottom piezoelectric surface region andphysically coupled to a portion of the backside metal electrode.According to an example, the present invention can provide the devicestructure resulting from the method described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the single crystal piezoelectric layer havinga top piezoelectric surface region and a bottom piezoelectric surfaceregion; forming topside metal electrode overlying the top piezoelectricsurface region; forming a topside micro-trench within a portion of thesingle crystal piezoelectric layer; forming a topside metal having atopside metal plug within the topside micro-trench; forming a backsidetrench within the substrate exposing the bottom piezoelectric surfaceregion, the backside trench underlying the topside metal electrode andthe topside micro-trench; forming a backside metal electrode underlyingor in proximity of the bottom piezoelectric surface region within thebackside trench, the backside metal electrode being electrically coupledto the topside metal; forming at least two metal pads for electricalconnections, wherein at least one metal pad is electrically coupled tothe topside metal electrode, and at least one metal pad is electricallycoupled to the backside metal electrode; forming a backside metal plugunderlying the bottom piezoelectric surface region within the backsidetrench, the backside metal plug being electrically coupled to thetopside metal plug and the backside metal electrode, wherein the topsidemicro-trench, the topside metal plug, and the backside metal plug form amicro-via; and subjecting the acoustic resonator device to a masked ionimplantation process; wherein the topside metal electrode, the singlecrystal piezoelectric layer, and the backside metal electrode form acentral resonator area.

In an example, the acoustic resonator device is subjected to the ionimplantation process during one of the following stages: before theforming of the topside metal electrode, before the forming of thebackside metal electrode, after the forming of the topside metalelectrode, and after the forming of the backside metal electrode. In anexample, the masked ion implantation process is bounded to a zonecharacterized by 500um outside the central resonator area, wherein thezone extends from and includes the central resonator area. In anexample, the masked ion implantation process uses one or more of thefollowing species: H, He, B, C, O, Fe, Mo, Ta, W, or other transitionmetal. In an example, the ion implantation process is characterized by adosage between 1 E+14 and 1 E+20 ions per cubic centimeter. According toan example, the present invention can provide the device structureresulting from the method described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the single crystal piezoelectric layer havinga top piezoelectric surface region and a bottom piezoelectric surfaceregion; forming topside metal electrode overlying the top piezoelectricsurface region; forming a topside micro-trench within a portion of thesingle crystal piezoelectric layer; forming a topside metal having atopside metal plug within the topside micro-trench; forming a backsidetrench within the substrate exposing the bottom piezoelectric surfaceregion and forming a substrate sidewall, the backside trench underlyingthe topside metal electrode and the topside micro-trench; forming abackside metal electrode underlying or in proximity of the bottompiezoelectric surface region within the backside trench, the backsidemetal electrode being electrically coupled to the topside metal; formingat least two metal pads for electrical connections, wherein at least onemetal pad is electrically coupled to the topside metal electrode, and atleast one metal pad is electrically coupled to the backside metalelectrode; and forming a backside metal plug underlying the bottompiezoelectric surface region within the backside trench, the backsidemetal plug being electrically coupled to the topside metal plug and thebackside metal electrode, wherein the topside micro-trench, the topsidemetal plug, and the backside metal plug form a micro-via; wherein thebackside metal electrode is spatially configured such that the distancebetween the backside metal electrode and the substrate sidewall rangesfrom about 0.1 um to about 500 um.

In an example, the topside metal electrode includes a topside electrodesurface area and the backside metal electrode includes a backsideelectrode surface area; wherein the backside electrode surface area isgreater than the topside electrode surface area such that a lateraldistance between an edge of the backside electrode surface area and anedge of the topside electrode surface area ranges from about 0.1 um toabout 500 um. In an example, the topside metal electrode includes atopside electrode surface area and the backside metal electrode includesa backside electrode surface area; wherein the topside electrode surfacearea is greater than the backside electrode surface area such that alateral distance between an edge of the topside electrode surface areaand an edge the backside electrode surface area ranges from about 0.1 umto about 500 um. According to an example, the present invention canprovide the device structure resulting from the method describedpreviously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the single crystal piezoelectric layer havinga top piezoelectric surface region and a bottom piezoelectric surfaceregion; forming topside metal electrode overlying the top piezoelectricsurface region; forming a topside micro-trench within a portion of thesingle crystal piezoelectric layer; forming a topside metal having atopside metal plug within the topside micro-trench; forming a backsidetrench within the substrate exposing the bottom piezoelectric surfaceregion, the backside trench underlying the topside metal electrode andthe topside micro-trench; forming a backside metal electrode underlyingor in proximity of the bottom piezoelectric surface region within thebackside trench, the backside metal electrode being electrically coupledto the topside metal; forming one or more frequency offset structurelayers within a vicinity of the single crystal piezoelectric layer;forming at least two metal pads for electrical connections, wherein atleast one metal pad is electrically coupled to the topside metalelectrode, and at least one metal pad is electrically coupled to thebackside metal electrode; and forming a backside metal plug underlyingthe bottom piezoelectric surface region within the backside trench, thebackside metal plug being electrically coupled to the topside metal plugand the backside metal electrode, wherein the topside micro-trench, thetopside metal plug, and the backside metal plug form a micro-via.

In an example, forming one or more frequency offset structure layersincludes forming a frequency offset structure layer overlying thetopside metal electrode. In an example, forming the one or morefrequency offset structure layers includes one of the following: apatterned sputtering process, a patterned evaporation and lift-offprocess, an evaporation and patterned etching process, a trimmingprocess, a laser ablation process, and an ion beam milling process. Inan example, forming one or more frequency offset structure layersincludes forming a frequency offset structure layer underlying or inproximity of the backside metal electrode. In an example, the frequencyoffset structure layer can include Mo, Al, W, Ru, AlN, SiN, or SiO₂. Inan example, forming one or more frequency offset structure layersincludes forming a topside frequency offset structure layer overlyingthe topside metal electrode and forming a backside frequency offsetstructure layer underlying or in proximity of the backside metalelectrode. According to an example, the present invention can providethe device structure resulting from the method described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the single crystal piezoelectric layer havinga top piezoelectric surface region and a bottom piezoelectric surfaceregion; forming a first topside metal electrode overlying a firstportion of the top piezoelectric surface region; forming a secondtopside metal electrode overlying a second portion of the toppiezoelectric surface region; forming a third topside metal electrodeoverlying a third portion of the top piezoelectric surface region;forming a backside trench within the substrate exposing the bottompiezoelectric surface region and forming a substrate sidewall, thebackside trench underlying the first, second, and third topside metalelectrodes; forming a backside metal plug underlying the bottompiezoelectric surface region within the backside trench; forming a firstbackside metal electrode underlying or in proximity of the bottompiezoelectric surface region and the first topside metal electrodewithin the backside trench, the first backside metal electrode beingelectrically coupled to the backside metal plug; forming a secondbackside metal electrode underlying or in proximity of the bottompiezoelectric surface region and the second topside metal electrodewithin the backside trench, the second backside metal electrode beingelectrically coupled to the backside metal plug; forming a thirdbackside metal electrode underlying or in proximity of the bottompiezoelectric surface region and the third topside metal electrodewithin the backside trench, the third backside metal electrode beingelectrically coupled to the backside metal plug; forming at least threemetal pads for electrical connections, wherein at least one metal pad iselectrically coupled to the first topside metal electrode, wherein atleast one metal pad is electrically coupled to the second topside metalelectrode, and wherein at least one metal par is electrically coupled tothe third topside metal electrode; and subjecting the multiple acousticresonator device to a masked ion implantation process; wherein the firsttopside metal electrode, the second topside metal electrode, the thirdtopside metal electrode, the single crystal piezoelectric layer, thefirst backside metal electrode, the second backside metal electrode, andthe third backside metal electrode form a central resonator area.

In an example, subjecting the multiple acoustic resonator device to amasked ion implantation process includes subjecting the multipleacoustic resonator device to the masked ion implantation process duringone of the following stages: before the forming of the topside metalelectrode, before the forming of the backside metal electrode, after theforming of the topside metal electrode, and after the forming of thebackside metal electrode. In an example, the masked ion implantationprocess is bounded to a zone characterized by 500 um outside the centralresonator area, wherein the zone extends from and includes the centralresonator area. In an example, the masked ion implantation process usesone or more of the following species: H, He, B, C, O, Fe, Mo, Ta, W, orother transition metal. In an example, the ion implantation process ischaracterized by a dosage between 1 E+14 and 1 E+20 ions per cubiccentimeter. According to an example, the present invention can providethe device structure resulting from the method described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the single crystal piezoelectric layer havinga top piezoelectric surface region and a bottom piezoelectric surfaceregion; forming topside metal electrode overlying a portion of the toppiezoelectric surface region, the topside metal electrode having atopside electrode surface region, a topside electrode perimeter, and oneor more topside electrode edges; forming a topside pillar structureoverlying a portion of the top piezoelectric surface region within avicinity of the topside metal electrode and outside of the topside metalelectrode perimeter; forming a topside micro-trench within a portion ofthe single crystal piezoelectric layer; forming a topside metal having atopside metal plug within the topside micro-trench; forming a backsidetrench within the substrate exposing the bottom piezoelectric surfaceregion and forming a substrate sidewall, the backside trench underlyingthe topside metal electrode and the topside micro-trench; forming abackside metal electrode underlying or in proximity of the bottompiezoelectric surface region within the backside trench, the backsidemetal electrode being electrically coupled to the topside metal, thebackside metal electrode having a backside electrode surface region, abackside electrode perimeter, and one or more backside electrode edges;forming at least two metal pads for electrical connections, wherein atleast one metal pad is electrically coupled to the topside metalelectrode, and at least one metal pad is electrically coupled to thebackside metal electrode; and forming a backside metal plug underlyingthe bottom piezoelectric surface region within the backside trench, thebackside metal plug being electrically coupled to the topside metal plugand the backside metal electrode, wherein the topside micro-trench, thetopside metal plug, and the backside metal plug form a micro-via.

In an example, the topside pillar structure comprises a metal material,a dielectric material, or a combination thereof. In an example, thetopside pillar structure is spatially configured substantially aroundthe topside electrode perimeter. In an example, the topside pillarstructure comprises a continuous pillar structure or one or morenon-continuous pillars. In an example, the topside metal electrodecomprises a topside electrode connection region; wherein forming thetopside pillar structure comprises forming the topside pillar structuresuch that the topside pillar structure includes a topside pillar gapregion within a vicinity of the topside electrode connection region. Inan example, the method further includes forming one or more backsidepillars underlying a portion of the topside pillar structure and aportion of the bottom piezoelectric surface region, wherein the one ormore backside pillars comprise a metal material, a dielectric material,or a combination thereof In an example, the method further includesforming one or more combination topside electrode pillars overlying aportion of the topside electrode surface region; wherein the one or morecombination topside electrode pillars comprises a metal pillar formedoverlying a dielectric pillar. In an example, the method furtherincludes forming one or more topside dielectric electrode pillarsoverlying a portion of the topside electrode surface region. In anexample, the one or more topside dielectric pillars are spatiallyconfigured at a distance of about 0.1 um to about 100 um to the topsideelectrode perimeter. In an example, the method further includes forminga topside electrode pillar structure overlying a portion of the topsideelectrode surface region and within the topside metal electrodeperimeter. In an example, the topside electrode pillar structurecomprises a metal material, a dielectric material, or a combinationthereof. In an example, the topside electrode pillar structure isspatially configured substantially along the topside electrodeperimeter. In an example, the topside electrode pillar structurecomprises a continuous pillar structure or one or more non-continuouspillars. In an example, forming the topside electrode pillar structurecomprises forming the topside electrode pillar structure such that thetopside electrode pillar structure includes a topside electrode pillargap region within a vicinity of the topside electrode connection region.

In an example, the method further includes forming one or more topsidedielectric electrode pillars overlying a portion of the topsideelectrode surface region; wherein at least one topside dielectricelectrode pillar physically contacts the topside electrode pillarstructure. The method further includes wherein the topside electrodepillar structure is spatially configured at a distance of about 0.1 umto about 100 um to the topside electrode perimeter. In an example,forming the topside pillar structure comprises forming a topsidedielectric pillar structure and a topside metal pillar structure;wherein the topside dielectric pillar structure is formed adjacent tothe topside metal electrode and the topside metal pillar structure isformed adjacent to the topside dielectric pillar structure. In anexample, the topside dielectric pillar structure comprises one or moreoverlapping portions overlying one or more portions of the topsideelectrode surface region. In an example, the topside metal pillarstructure comprises one or more overlapping portions overlying one ormore portions of the topside dielectric pillar structure.

In an example, the method further includes forming one or more backsidedielectric pillars underlying a portion of the topside pillar structureand one or more portions of the bottom piezoelectric surface region; andforming one or more backside metal pillars underlying a portion of thetopside pillar structure and one or more portions of the bottompiezoelectric surface region; wherein the one or more backsidedielectric pillars are formed adjacent to the backside metal electrodeand the one or more backside metal pillars are formed adjacent to theone or more backside dielectric pillars. In an example, at least onebackside dielectric pillar comprises an underlapping portion underlyinga portion of the bottom metal electrode. In an example, at least onebackside dielectric pillar comprises an underlapping portion underlyinga portion of the bottom metal electrode. In an example, forming thetopside pillar structure comprises forming a topside dielectric pillarstructure and a topside metal pillar structure; wherein the topsidedielectric pillar structure is formed adjacent to the topside metalelectrode and the topside metal pillar structure is formed overlying thetopside dielectric pillar structure. In an example, the topsidedielectric pillar structure comprises one or more overlapping portionsoverlying one or more portions of the topside electrode surface region.In an example, the method further includes removing a portion of thesingle crystal piezoelectric layer to form a topside piezo cavity;wherein forming the topside metal electrode comprises forming thetopside metal electrode such that at least a portion of the topsidemetal electrode is spatially configured within the topside piezo cavity.In an example, forming the topside pillar structure comprises formingthe topside pillar structure within the topside piezo cavity. Accordingto an example, the present invention can provide the device structureresulting from the method described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the single crystal piezoelectric layer havinga top piezoelectric surface region and a bottom piezoelectric surfaceregion; forming topside metal electrode overlying a portion of the toppiezoelectric surface region, the topside metal electrode having atopside electrode surface region, a topside electrode perimeter, and oneor more topside electrode edges; forming a topside micro-trench within aportion of the single crystal piezoelectric layer; forming a topsidemetal having a topside metal plug within the topside micro-trench;forming a backside trench within the substrate exposing the bottompiezoelectric surface region and forming a substrate sidewall, thebackside trench underlying the topside metal electrode and the topsidemicro-trench; forming a backside metal electrode underlying or inproximity of the bottom piezoelectric surface region within the backsidetrench, the backside metal electrode being electrically coupled to thetopside metal, the backside metal electrode having a backside electrodesurface region, a backside electrode perimeter, and one or more backsideelectrode edges; forming a backside pillar structure underlying aportion of the bottom piezoelectric surface region within a vicinity ofthe backside metal electrode and outside of the backside metal electrodeperimeter; forming at least two metal pads for electrical connections,wherein at least one metal pad is electrically coupled to the topsidemetal electrode, and at least one metal pad is electrically coupled tothe backside metal electrode; and forming a backside metal plugunderlying the bottom piezoelectric surface region within the backsidetrench, the backside metal plug being electrically coupled to thetopside metal plug and the backside metal electrode, wherein the topsidemicro-trench, the topside metal plug, and the backside metal plug form amicro-via.

In an example, the backside pillar structure comprises a metal material,a dielectric material, or a combination thereof. In an example, thebackside pillar structure is spatially configured substantially aroundthe backside electrode perimeter. In an example, the backside pillarstructure comprises a continuous pillar structure or one or morenon-continuous pillars. In an example, the backside metal electrodecomprises a backside electrode connection region; wherein forming thebackside pillar structure comprises forming the backside pillarstructure such that the backside pillar structure includes a backsidepillar gap region within a vicinity of the backside electrode connectionregion. In an example, the method further includes forming one or moretopside pillars overlying a portion of the topside pillar structure anda portion of the top piezoelectric surface region, wherein the one ormore topside pillars comprise a metal material, a dielectric material,or a combination thereof. In an example, forming one or more insulatedbackside electrode pillars underlying a portion of the backsideelectrode surface region; wherein the one or more insulated backsideelectrode pillars comprises a metal pillar formed underlying adielectric pillar. In an example, the method further includes formingone or more backside dielectric electrode pillars underlying a portionof the backside electrode surface region. In an example, the one or morebackside dielectric pillars are spatially configured at a distance ofabout 0.1 um to about 100 um to the backside electrode perimeter.

In an example, the method further includes forming a backside electrodepillar structure underlying a portion of the backside electrode surfaceregion and within the backside metal electrode perimeter. In an example,the backside electrode pillar structure comprises a metal material, adielectric material, or a combination thereof. In an example, thebackside electrode pillar structure is spatially configuredsubstantially along the backside electrode perimeter. In an example, thebackside electrode pillar structure comprises a continuous pillarstructure or one or more non-continuous pillars. In an example, formingthe backside electrode pillar structure comprises forming the backsideelectrode pillar structure such that the backside electrode pillarstructure includes a backside electrode pillar gap region within avicinity of the backside electrode connection region. In an example, themethod further includes forming one or more backside dielectricelectrode pillar underlying a portion of the backside electrode surfaceregion; wherein at least one backside dielectric electrode pillarphysically contacts the backside electrode pillar structure. In anexample, the backside electrode pillar structure is spatially configuredat a distance of about 0.1 um to about 100 um to the backside electrodeperimeter. In an example, forming the backside pillar structurecomprises forming a backside dielectric pillar structure and a backsidemetal pillar structure; wherein the backside dielectric pillar structureis formed adjacent to the backside metal electrode and the backsidemetal pillar structure is formed adjacent to the backside dielectricpillar structure. In an example, the backside dielectric pillarstructure comprises one or more underlapping portions underlying one ormore portions of the backside electrode surface region. In an example,the backside metal pillar structure comprises one or more underlappingportions underlying one or more portions of the backside dielectricpillar structure.

In an example, the method further includes forming one or more topsidedielectric pillars overlying a portion of the backside pillar structureand one or more portions of the top piezoelectric surface region; andforming one or more topside metal pillars overlying a portion of thebackside pillar structure and one or more portions of the toppiezoelectric surface region; wherein the one or more topside dielectricpillars are formed adjacent to the topside metal electrode and the oneor more topside metal pillars are formed adjacent to the one or moretopside dielectric pillars. In an example, at least one topsidedielectric pillar comprises an overlapping portion overlying a portionof the topside metal electrode. In an example, at least one topsidemetal pillar comprises an overlapping portion overlying at least onetopside dielectric pillar. In an example, forming the backside pillarstructure comprises forming a backside dielectric pillar structure and abackside metal pillar structure; wherein the backside dielectric pillarstructure is formed adjacent to the backside metal electrode and thebackside metal pillar structure is formed underlying the backsidedielectric pillar structure. In an example, the backside dielectricpillar structure comprises one or more underlapping portions underlyingone or more portions of the backside electrode surface region.

In an example, the method further includes removing a portion of thesingle crystal piezoelectric layer to form a backside piezo cavity;wherein forming the backside metal electrode comprises forming thebackside metal electrode such that at least a portion of the backsidemetal electrode is spatially configured within the backside piezocavity. In an example, forming the backside pillar structure comprisesforming the backside pillar structure within the backside piezo cavity.According to an example, the present invention can provide the devicestructure resulting from the method described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the single crystal piezoelectric layer havinga top piezoelectric surface region and a bottom piezoelectric surfaceregion; forming topside metal electrode overlying a portion of the toppiezoelectric surface region, the topside metal electrode having atopside electrode surface region, a topside electrode perimeter, and oneor more topside electrode edges; forming a topside pillar structureoverlying a portion of the top piezoelectric surface region within avicinity of the topside metal electrode and outside of the topside metalelectrode perimeter; forming a topside electrode pillar structureoverlying a portion of the topside electrode surface region and withinthe topside metal electrode perimeter; forming a topside micro-trenchwithin a portion of the single crystal piezoelectric layer; forming atopside metal having a topside metal plug within the topsidemicro-trench; forming a backside trench within the substrate exposingthe bottom piezoelectric surface region and forming a substratesidewall, the backside trench underlying the topside metal electrode andthe topside micro-trench; forming a backside metal electrode underlyingor in proximity of the bottom piezoelectric surface region within thebackside trench, the backside metal electrode being electrically coupledto the topside metal, the backside metal electrode having a backsideelectrode surface region, a backside electrode perimeter, and one ormore backside electrode edges; forming a backside pillar structureunderlying a portion of the bottom piezoelectric surface region within avicinity of the backside metal electrode and outside of the backsidemetal electrode perimeter; forming a backside electrode pillar structureunderlying a portion of the backside electrode surface region and withinthe backside metal electrode perimeter; forming at least two metal padsfor electrical connections, wherein at least one metal pad iselectrically coupled to the topside metal electrode, and at least onemetal pad is electrically coupled to the backside metal electrode; andforming a backside metal plug underlying the bottom piezoelectricsurface region within the backside trench, the backside metal plug beingelectrically coupled to the topside metal plug and the backside metalelectrode, wherein the topside micro-trench, the topside metal plug, andthe backside metal plug form a micro-via. According to an example, thepresent invention can provide the device structure resulting from themethod described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the piezoelectric layer having a toppiezoelectric surface region and a bottom piezoelectric surface region;forming a topside energy confinement structure overlying the toppiezoelectric surface region, the topside energy confinement structurebeing characterized by a topside structure geometric area and a topsidestructure perimeter, the topside energy confinement structure having atleast one portion removed forming a topside structure break region;forming a topside metal electrode overlying the top piezoelectricsurface region and within the topside energy confinement structure, thetopside metal electrode being characterized by a topside electrodegeometric area; and forming a backside trench within the substrateexposing the bottom piezoelectric surface region, the backside trenchunderlying the topside metal electrode, the backside trench beingcharacterized by a cavity geometric area.

In an example, wherein the topside metal electrode is formed adjacent tothe topside energy confinement structure. In an example, forming atopside sandbar structure overlying the top piezoelectric surface regionwithin a vicinity of the topside structure break region; wherein thetopside sandbar structure is spatially configured outside the topsidestructure perimeter of the topside energy confinement structure. In anexample, the topside sandbar structure is spatially configured with agap having a distance of about 0.1 um to about 100 um to the topsidemetal electrode. In an example, the topside energy confinement structurecomprises a dielectric material, a metal material, or a combination ofdielectric and metal materials. In an example, the topside energyconfinement structure comprises a castellation pattern characterized bya repeated castellation shape, wherein the castellation shape includes asquare, a triangle, a polygonal shape, or a non-polygonal shape. In anexample, the topside sandbar structure comprises a dielectric material,a metal material, or a combination of dielectric and metal materials. Inan example, the topside sandbar structure comprises a straight sandbarstructure, a curved sandbar structure, or an angled sandbar structure.In an example, each of the topside electrode geometric area, the topsidestructure geometric area, and the cavity geometric area includes acircle, an ellipses, skew non-polygonal shapes, irregular shapes, or apolygonal shape having n sides, where n is greater than or equal tothree; wherein the topside electrode geometric area, the topsidestructure geometric area, and the cavity geometric area can becharacterized by geometric areas having similar or dissimilar shapes.According to an example, the present invention can provide the devicestructure resulting from the method described previously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the piezoelectric layer having a toppiezoelectric surface region and a bottom piezoelectric surface region;forming a backside trench within the substrate exposing the bottompiezoelectric surface region, the backside trench being characterized bya cavity geometric area; forming a backside energy confinement structureunderlying the bottom piezoelectric surface region, the backside energyconfinement structure being characterized by a backside structuregeometric area and a backside structure perimeter, the backside energyconfinement structure having at least one portion removed forming abackside structure break region; and forming a backside metal electrodeunderlying the bottom piezoelectric surface region and within thebackside energy confinement structure, the backside metal electrodebeing characterized by a backside electrode geometric area.

In an example, wherein the backside metal electrode is formed adjacentto the backside energy confinement structure. In an example, the methodfurther includes forming a backside sandbar structure underlying thebottom piezoelectric surface region within a vicinity of the backsidestructure break region; wherein the backside sandbar structure isspatially configured outside the backside structure perimeter of thebackside energy confinement structure. In an example, the backsidesandbar structure is spatially configured with a gap having a distanceof about 0.1 um to about 100 um to the backside metal electrode. In anexample, the backside energy confinement structure comprises adielectric material, a metal material, or a combination of dielectricand metal materials. In an example, the backside energy confinementstructure comprises a castellation pattern characterized by a repeatedcastellation shape, wherein the castellation shape includes a square, atriangle, a polygonal shape, or a non-polygonal shape. In an example,the backside sandbar structure comprises a dielectric material, a metalmaterial, or a combination of dielectric and metal materials. In anexample, the backside sandbar structure comprises a straight sandbarstructure, a curved sandbar structure, or an angled sandbar structure.In an example, each of the backside electrode geometric area, thebackside structure geometric area, and the cavity geometric areaincludes a circle, an ellipses, skew non-polygonal shapes, irregularshapes, or a polygonal shape having n sides, where n is greater than orequal to three; wherein the backside electrode geometric area, thebackside perimeter structure geometric area, and the cavity geometricarea can be characterized by geometric areas having similar ordissimilar shapes. According to an example, the present invention canprovide the device structure resulting from the method describedpreviously.

According to an example, the present invention provides a structure anda method of fabricating an acoustic resonator or filter device. Themethod can include providing a substrate having a substrate surfaceregion; forming a single crystal piezoelectric layer overlying thesubstrate surface region, the piezoelectric layer having a toppiezoelectric surface region and a bottom piezoelectric surface region;forming a topside energy confinement structure overlying the toppiezoelectric surface region, the topside energy confinement structurebeing characterized by a topside structure geometric area and a topsidestructure perimeter, the topside energy confinement structure having atleast one portion removed forming a topside structure break region;forming a topside metal electrode overlying the top piezoelectricsurface region and within the topside energy confinement structure, thetopside metal electrode being characterized by a topside electrodegeometric area; forming a topside sandbar structure overlying the toppiezoelectric surface region within a vicinity of the topside structurebreak region; forming a backside trench within the substrate exposingthe bottom piezoelectric surface region, the backside trench underlyingthe topside metal electrode and the topside micro-trench, the backsidetrench being characterized by a cavity geometric area; forming abackside energy confinement structure underlying the bottompiezoelectric surface region, the backside energy confinement structurebeing characterized by a backside structure geometric area, the backsideenergy confinement structure having at least one portion removed forminga backside structure break region; forming a backside metal electrodeunderlying the bottom piezoelectric surface region and within thebackside energy confinement structure, the backside metal electrodebeing characterized by a backside electrode geometric area; and forminga backside sandbar structure underlying the bottom piezoelectric surfaceregion within a vicinity of the backside structure break region.According to an example, the present invention can provide the devicestructure resulting from the method described previously.

According to an example, the present invention can provide a method forfabricating a single crystal III-Nitride based, surface acoustic waveresonator or filter device through lithographically placinginterdigitated features on the top or bottom surface of the singlecrystal material. This acoustic resonator or filter device can becombined with any of the features described previously. According to anexample, the present invention can provide the device structureresulting from the method described previously.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. As an example, the packaged device can include any combination ofelements described above, as well as outside of the presentspecification. As used herein, the term “substrate” can mean the bulksubstrate or can include overlying growth structures such as analuminum, gallium, or ternary compound of aluminum and gallium andnitrogen containing epitaxial region, or functional regions,combinations, and the like. Therefore, the above description andillustrations should not be taken as limiting the scope of the presentinvention which is defined by the appended claims.

What is claimed is:
 1. A method for fabricating an acoustic resonator orfilter device, the method comprising: providing a substrate having asubstrate surface region and a substrate backside cavity region; forminga piezoelectric layer overlying the substrate surface region, thepiezoelectric layer having a top piezoelectric surface region and abottom piezoelectric surface region; forming a topside metal electrodeoverlying the top piezoelectric surface region; forming a topsidemicro-trench within a portion of the piezoelectric layer; forming abackside metal electrode underlying or in proximity of the bottompiezoelectric surface region within the substrate backside cavityregion, the backside metal electrode being electrically coupled to amicro-via configured within the topside micro-trench; and removing aportion of the piezoelectric layer to form a first topside groove on thetop piezoelectric surface region.
 2. The method of claim 1 wherein thepiezoelectric layer comprises an essentially single crystal material ora polycrystalline material.
 3. The method of claim 1 wherein forming thetopside metal electrode and the backside metal electrode includes anedge profile fabrication process to form one or more topside metalelectrode edges and one or more backside metal electrode edges, whereinthe edge profile fabrication process can be selected from the following:a patterned sputtering process, a patterned evaporation and lift-offprocess, an evaporation and patterned etching process, a trimmingprocess, a laser ablation process, and an ion beam milling process. 4.The method of claim 1 wherein the topside metal electrode includes oneor more topside metal electrode edges being characterized by a topsideelectrode edge geometric shape; and wherein the topside electrode edgegeometric shape includes one of the following shapes: a down slope edge,an up slope edge, an up and down slope edge, an up-flat-down slope edge,a stair steps edge, and a circular edge.
 5. The method of claim 4wherein forming the topside metal electrode includes forming the topsidemetal electrode such that the topside electrode edge geometric shape isspatially configured above or within the top piezoelectric surfaceregion.
 6. The method of claim 1 wherein the topside metal electrodeincludes a groove formed within the topside metal electrode within avicinity of the one or more topside electrode edges.
 7. The method ofclaim 1 wherein the backside metal electrode includes one or morebackside metal electrode edges being characterized by a backsideelectrode edge geometric shape; and wherein the backside electrode edgegeometric shape includes one of the following shapes: a down slope edge,an up slope edge, an up and down slope edge, an up-flat-down slope edge,a stair steps edge, and a circular edge.
 8. The method of claim 7wherein forming the backside metal electrode includes forming thebackside metal electrode such that backside electrode edge geometricshape is spatially configured within or below the bottom piezoelectricsurface region.
 9. The method of claim 1 wherein the backside metalelectrode includes a groove formed within the backside metal electrodewithin a vicinity of the one or more backside electrode edges.
 10. Themethod of claim 1 wherein the topside metal electrode includes one ormore topside metal electrode edges being characterized by a topsideelectrode edge geometric shape; and wherein the backside metal electrodeincludes one or more backside metal electrode edges being characterizedby a backside electrode edge geometric shape; and wherein each of thetopside electrode edge geometric shape and the backside electrode edgeshape includes one of the following shapes: a down slope edge, an upslope edge, an up and down slope edge, an up-flat-down slope edge, astair steps edge, and a circular edge; wherein the topside metalelectrode includes a groove formed within the topside metal electrodewithin a vicinity of the one or more topside electrode edges; andwherein the backside metal electrode includes a groove formed within thebackside metal electrode within a vicinity of the one or more backsideelectrode edges.
 11. The method of claim 1 wherein the first topsidegroove is spatially configured overlying the backside trench.
 12. Themethod of claim 1 further comprising removing a portion of thepiezoelectric layer to form a second topside groove on the toppiezoelectric surface region; wherein the second topside groove isspatially configured within the vicinity of an edge of the topside metalelectrode and the first groove.
 13. The method of claim 12 wherein thefirst topside groove is spatially configured overlying a portion of thebackside trench and the second topside groove is spatially configuredoverlying a portion of the substrate.
 14. A method for fabricating anacoustic resonator or filter device, the method comprising: providing asubstrate having a substrate surface region and a substrate backsidecavity region; forming a piezoelectric layer overlying the substratesurface region, the piezoelectric layer having a top piezoelectricsurface region and a bottom piezoelectric surface region; forming atopside metal electrode overlying the top piezoelectric surface region;forming a topside micro-trench within a portion of the piezoelectriclayer; forming a backside metal electrode underlying or in proximity ofthe bottom piezoelectric surface region within the substrate backsidecavity region, the backside metal electrode being electrically coupledto a micro-via configured within the topside micro-trench; removing aportion of the piezoelectric layer to form a first topside groove on thetop piezoelectric surface region; and removing a portion of thepiezoelectric layer to form a first backside groove on the bottompiezoelectric surface region.
 15. The method of claim 14 wherein thepiezoelectric layer comprises an essentially single crystal material ora polycrystalline material.
 16. The method of claim 13 wherein the firstbackside groove is spatially configured within the backside trench. 17.The method of claim 14 further comprising removing a portion of thepiezoelectric layer to form a second backside groove on the bottompiezoelectric surface region; wherein the second backside groove isspatially configured within the vicinity of an edge of the backsidemetal electrode and the first backside groove.
 18. The method of claim17 wherein the first backside groove is spatially configured within aportion of the backside trench and the second backside groove isspatially configured within a portion of the backside trench.
 19. Amethod for fabricating an acoustic resonator or filter device, themethod comprising: providing a substrate having a substrate surfaceregion and a substrate backside cavity region; forming a piezoelectriclayer overlying the substrate surface region, the piezoelectric layerhaving a top piezoelectric surface region and a bottom piezoelectricsurface region; forming a topside metal electrode overlying the toppiezoelectric surface region; forming a topside micro-trench within aportion of the piezoelectric layer; forming a backside metal electrodeunderlying or in proximity of the bottom piezoelectric surface regionwithin the substrate backside cavity region, the backside metalelectrode being electrically coupled to a micro-via configured withinthe topside micro-trench; removing a portion of the piezoelectric layerto form a first topside groove on the top piezoelectric surface region;removing a portion of the piezoelectric layer to form a first topsidegroove on the top piezoelectric surface region; and removing a portionof the piezoelectric layer to form a first backside groove on the bottompiezoelectric surface region.
 20. The method of claim 19 wherein thepiezoelectric layer comprises an essentially single crystal material ora polycrystalline material.
 21. A method for fabricating an acousticresonator or filter device, the method comprising: providing a substratehaving a substrate surface region and a substrate backside cavityregion; forming a piezoelectric layer overlying the substrate surfaceregion, the piezoelectric layer having a top piezoelectric surfaceregion and a bottom piezoelectric surface region; forming a topsidemetal electrode overlying the top piezoelectric surface region; forminga topside micro-trench within a portion of the piezoelectric layer;forming a backside metal electrode underlying or in proximity of thebottom piezoelectric surface region within the substrate backside cavityregion, the backside metal electrode being electrically coupled to amicro-via configured within the topside micro-trench; removing a portionof the piezoelectric layer to form a first topside groove on the toppiezoelectric surface region; removing a portion of the piezoelectriclayer to form a topside groove on the top piezoelectric surface region;and wherein forming the topside metal electrode includes forming thetopside metal electrode overlying the top piezoelectric surface regionwithin the topside groove.
 22. The method of claim 21 wherein thepiezoelectric layer comprises an essentially single crystal material ora polycrystalline material.
 23. A method for fabricating an acousticresonator or filter device, the method comprising: providing a substratehaving a substrate surface region and a substrate backside cavityregion; forming a piezoelectric layer overlying the substrate surfaceregion, the piezoelectric layer having a top piezoelectric surfaceregion and a bottom piezoelectric surface region; forming a topsidemetal electrode overlying the top piezoelectric surface region; forminga topside micro-trench within a portion of the piezoelectric layer;forming a backside metal electrode underlying or in proximity of thebottom piezoelectric surface region within the substrate backside cavityregion, the backside metal electrode being electrically coupled to amicro-via configured within the topside micro-trench; removing a portionof the piezoelectric layer to form a first topside groove on the toppiezoelectric surface region; removing a portion of the piezoelectriclayer to form a backside groove on the bottom piezoelectric surfaceregion; and wherein forming the backside metal electrode includesforming the backside metal electrode underlying the bottom piezoelectricsurface region within the backside groove.
 24. The method of claim 23wherein the piezoelectric layer comprises an essentially single crystalmaterial or a polycrystalline material.
 25. A method for fabricating anacoustic resonator or filter device, the method comprising: providing asubstrate having a substrate surface region and a substrate backsidecavity region; forming a piezoelectric layer overlying the substratesurface region, the piezoelectric layer having a top piezoelectricsurface region and a bottom piezoelectric surface region; forming atopside metal electrode overlying the top piezoelectric surface region;forming a topside micro-trench within a portion of the piezoelectriclayer; forming a backside metal electrode underlying or in proximity ofthe bottom piezoelectric surface region within the substrate backsidecavity region, the backside metal electrode being electrically coupledto a micro-via configured within the topside micro-trench; removing aportion of the piezoelectric layer to form a first topside groove on thetop piezoelectric surface region; removing a portion of thepiezoelectric layer to form a topside groove on the top piezoelectricsurface region; wherein forming the topside metal electrode includesforming the topside metal electrode overlying the top piezoelectricsurface region within the topside groove; removing a portion of thepiezoelectric layer to form a backside groove on the bottompiezoelectric surface region; and wherein forming the backside metalelectrode includes forming the backside metal electrode underlying thebottom piezoelectric surface region within the backside groove.
 26. Themethod of claim 25 wherein the piezoelectric layer comprises anessentially single crystal material or a polycrystalline material.
 27. Amethod for fabricating an acoustic resonator or filter device, themethod comprising: providing a substrate having a substrate surfaceregion and a substrate backside cavity region; forming a piezoelectriclayer overlying the substrate surface region, the piezoelectric layerhaving a top piezoelectric surface region and a bottom piezoelectricsurface region; forming a topside metal electrode overlying the toppiezoelectric surface region; forming a topside micro-trench within aportion of the piezoelectric layer; forming a backside metal electrodeunderlying or in proximity of the bottom piezoelectric surface regionwithin the substrate backside cavity region, the backside metalelectrode being electrically coupled to a micro-via configured withinthe topside micro-trench; removing a portion of the piezoelectric layerto form a first topside groove on the top piezoelectric surface region;and forming a topside edge border material overlying and physicallycoupled to a portion of the top piezoelectric surface region andphysically coupled to a portion of the topside metal electrode.
 28. Themethod of claim 27 wherein the piezoelectric layer comprises anessentially single crystal material or a polycrystalline material. 29.The method of claim 27 wherein the topside edge border material includesa metal material or a dielectric material.
 30. The method of claim 27wherein forming the topside edge border material includes forming thetopside edge border material overlying a portion of the topside metalelectrode.
 31. The method of claim 27 further comprising removing aportion of the topside metal electrode within a vicinity of the topsideedge border material to form a topside electrode groove.
 32. A methodfor fabricating an acoustic resonator or filter device, the methodcomprising: providing a substrate having a substrate surface region anda substrate backside cavity region; forming a piezoelectric layeroverlying the substrate surface region, the piezoelectric layer having atop piezoelectric surface region and a bottom piezoelectric surfaceregion; forming a topside metal electrode overlying the toppiezoelectric surface region; forming a topside micro-trench within aportion of the piezoelectric layer; forming a backside metal electrodeunderlying or in proximity of the bottom piezoelectric surface regionwithin the substrate backside cavity region, the backside metalelectrode being electrically coupled to a micro-via configured withinthe topside micro-trench; removing a portion of the piezoelectric layerto form a first topside groove on the top piezoelectric surface region;and forming a backside edge border material underlying and physicallycoupled to a portion of the bottom piezoelectric surface region andphysically coupled to a portion of the backside metal electrode.
 33. Themethod of claim 32 wherein the piezoelectric layer comprises anessentially single crystal material or a polycrystalline material. 34.The method of claim 32 wherein the backside edge border materialincludes a metal material or a dielectric material.
 35. The method ofclaim 32 wherein forming the backside edge border material includesforming the backside edge border material overlying a portion of thebackside metal electrode.
 36. The method of claim 35 further comprisingremoving a portion of the backside metal electrode within a vicinity ofthe backside edge border material to form a backside electrode groove.37. A method for fabricating an acoustic resonator or filter device, themethod comprising: providing a substrate having a substrate surfaceregion and a substrate backside cavity region; forming a piezoelectriclayer overlying the substrate surface region, the piezoelectric layerhaving a top piezoelectric surface region and a bottom piezoelectricsurface region; forming a topside metal electrode overlying the toppiezoelectric surface region; forming a topside micro-trench within aportion of the piezoelectric layer; forming a backside metal electrodeunderlying or in proximity of the bottom piezoelectric surface regionwithin the substrate backside cavity region, the backside metalelectrode being electrically coupled to a micro-via configured withinthe topside micro-trench; removing a portion of the piezoelectric layerto form a first topside groove on the top piezoelectric surface region;and forming an topside edge border material overlying and physicallycoupled to a portion of the top piezoelectric surface region andphysically coupled to a portion of the topside metal electrode; andforming an backside edge border material underlying and physicallycoupled to a portion of the bottom piezoelectric surface region andphysically coupled to a portion of the backside metal electrode.
 38. Themethod of claim 37 wherein the piezoelectric layer comprises anessentially single crystal material or a polycrystalline material.